Last month, I explained
why I use generic desktops and laptops running open source software.
and inexpensive. But this presumes you can fix them. I believe that
even those with no
hardware training (like me), can identify and fix most hardware
problems. To prove it, here’s a quick guide. Feel free to
add whatever I’ve missed.Here’s the outline —
- Before you open up your
computer, remember to unplug it. Unplug
- Ground yourself! A
than you get from walking across the carpet kills
circuitry. Buy a $5 US
- Enter error messages to Google to see how others fixed your
problem. Why reinvent the wheel?
- Download your computer’s User
Guide and Field Service Manual
if you lack hardcopies.
- A 2″ longSwiss
Army Knife includes a tapered screwdriver that fits nearly all PC
screws for under $15 US.
The first step in fixing a problem is to identify it. Don’t jump to conclusions. Run
free diagnostic software for problem identification:
- Boot-time diagnostics are available in many computers’
panels. Some come with diagnostic CDs.
- Download free test discs like Hiren’s Boot CD, the Computer
Repair Utility Kit,The
Inquisitor, andthe PC Repair System.
- Live Linuxes like the Ultimate
and System Rescue CD
have hardware testing tools plus software aids.
Don’t know if your problem is hardware or software? Run a different
operating system. If the problem disappears, it’s software. If you’re
using Windows, boot a live Linux CD to determine if your problem is
or a hardware issue.
Now that I’ve told you not to jump to conclusions, I’m forced to do
that in this article, due to space limitations. My bad!
There could be many
causes for this one — a short circuit, damagedelectronics, and
more. Most random shutdowns are
caused by overheating. Laptops
prone to this because they cram so
much circuitry into too small a package for easy cooling.
Every computer has internal sensors that immediately shut down the
system to prevent electronics damage if the temperature gets too high.
Since you can not relate the timing
of the shutdowns to your actions, they appear random.
To fix overheating,ensure all fan(s) are spinning
they should. Unclog the air vents. Make
sure you aren’t blocking the vents by placing the laptop on your lap or
desktop up against a flush surface. Don’t pre-heat a laptop by
leaving it in the direct
sunlight or in a car window. Use the computer in an air-conditioned
Open the computer and
remove dust, especially that coating circuitry. Since static electricity kills
electronics, don’t rub down circuitry
with a dust rag. Blow it out with an inexpensive canister of compressed
If this doesn’t fix your problem, you may
need to replace the fan(s). Fans burn out as their ball bearings fail.
If the computer has a CPU heat sink (a
metal flange that draws heat away from the CPU), you may need to
re-seat it. Anyone who’s downloaded their computer’s service
manual can perform these procedures so long as they exercise care. Here are good generic
instructions with pictures.
flip the Power switch on and your computer appears
to start up. The power light goes On, the fans spin, maybe the disks
kick — but nothing further happens. You can’t get into the
computer’s configuration panels to
perform problem determination.
Some brands will give you “beep codes” or “blink codes” to tell you
what’s wrong. Look in the doc to decode them.
If not, this one’s tough to diagnose. You
a methodology that helps you find the problem.
you can’t get to the BIOS panels, you have a hardware problem. Turn off
computer, open it up,
and write down where every wire, insertable adapter card, and connector
attaches to the motherboard and the devices. Record this so you can
disconnect every wire or plug fromthe motherboard,
for the power connectors from the power supply. Detach all devices.
Remove all adapter
cards and all memory.
you’re down to a naked motherboard with its CPU, attached to the power
supply. Insert one good memory stick into the first slot nearest the
CPU, attach a working display (with a video card you know works, if
necessary), and turn on the computer. If you can’t
configuration or BIOS panels now, the motherboard or CPU
circuitry may be bad. Visually inspect the motherboard for leakage,
near the capacitors and battery. You
might succeed in cleaning up leakage, but most of those boards are
If the system does display the BIOS panels, the motherboard and its
embedded circuitry is good. One at a time, reattach each connector or
cable or insertable adapter card. After reconnecting an item,
turn on the computer. If you can still get into the BIOS configuration
panels, you know thatwhatever you just attached is
notcausing the freeze-up or failure. As soon as you attach an
item and the computer dies, you know that that
component was the problem.
an example. My friend’s year-old computer completely baffled him. It
start up, display the “HP Welcome” panel, and freeze. He
couldn’t get into the configuration panels. I stripped the system down
to the Motherboard+CPU+OneMemoryStick+Display+PowerSupply. Then I
powered on and got into
the BIOS panels, so I knew the motherboard and CPU were good.
Then I attached each item, one
at a time, and booted after each, and got into
the BIOS panels. Until Iattached the SATA disk drive! Then the
symptom re-appeared. We replaced the defective disk and the
system has worked fine since.
This methodology is time-consuming but it’s a surefire way to
identify a defective component. It identifies these problems:
- Improperly seated or burned out adapter cards
- Faulty devices
- Loose or bad connector cables to devices
- Wires that aren’t properly connected to the motherboard
- Improperly seated or defective memory sticks
What if your computer won’t turn on at all? Check the power supply and
ensure the computer is getting electricity. Was it
plugged into a live wall socket with a good power
cord? Test the socket with a lamp. Don’t
assume that one socket in a
power strip is workingjust because the other sockets
in the strip work. If you just upgraded memory verify the
the ram sticks.
Check the wire that goes from the Power On button to the motherboard.
If this doesn’t connect you’re not turning on the computer at
all. Is the power supply (PS) working? Did its fan
spin when powered on?
Is the PS properly connected to the motherboard? If you have
a spare try the motherboard with another power supply to see
if a burnt out PS is the problem. Find how to diagnose PS problems here. If you have a
volt-ohm meter (VOM) verify the current.
If these procedures don’t work, try the disassembly/reassembly
Sometimes you’ll find a short caused by improper connection this way.
the computer boots and gets into the Windows
start-up process, then freezes or fails, nearly always you have a
Windows software issue rather than a hardware problem. To find out for
sure, boot a
Linux Live CD. If everything works you have a Windows problem.
This is a hardware
article so I won’t address how to fix Windows.
your computer loses the date or time across sessions, you probably have
a dead battery. This is the little
round watch-type battery that keeps configuration information across
sessions, the CMOS
Before you replace the battery, write it down any unique configuration
information still in your BIOS panels. Then, pry it out and replace it.
They cost only a few bucks. After you install the new battery, update
the date and time and re-enter any unique configuration info into the
BIOS. Here’s how the battery might look on a
Courtesy: www.PCTechNotes.com and www.TechNibble.com
If you have a rollerball mouse and it tracks poorly, you need to clean
it. Open up the
bottom and ensure all lint is removed from the
rollers that contact the mouse ball. Don’t let any debris from this
cleaning fall elsewhere inside the mouse.
If your mouse is
optical, the only cleaning you need to do is to ensure that no
lint is clogging the optical opening beneath the mouse. Sometimes optical mice don’t track well on
glossy or transparent
surfaces, including some mouse pads.
If your plug-in mouse doesn’t work at all, ensure the
connection is secure. Verify the operating system is using a valid
mouse driver. Test
your questionable mouse on another computer or plug in a different
mouse to your
computer. Reboot and test. This shows whether you
a dead mouse rather than a software issue.
your mouse is wireless, the most common problems are: (1) a dead
battery (2) a wireless connection problem (3) device drivers that are
not correctly installed, or (4) a dead mouse. Check the batteries
first. Ensure the wireless adapter or USB linking
device is securely
in. Verify the drivers. Use the wireless control program to
diagnose and resync the mouse. Tryresyncing the mouse by powering
everything down, then rebooting.
If you prevent
food, hair and
other debris from falling inside your keyboard, you’ve avoided
90% of all
problems. To clean a keyboard, detach it, turn it upside down and
vigorously shake it. If this
carefully pry off sticky keys and
eliminate the gunk underneath.
Desktop keyboards are so cheap you might as
well buy a new one for all but the simplest repairs. Laptops are
another matter, with their embedded keyboards. See how to repair
individual keys here.You
can also buy a replacement keyboard for your specific model of laptop
and install it. This is generically described here
andmodel-specificinformation is available here.Hiren’s Boot CD
includeskeyboard testing programs.
What if you spill water or a drink onto your keyboard? Turn everything
Pull the power cord or push the Off button. Do not take the time to perform a graceful
shutdown! The longer electricity goes
through the electronics the greater the chance for permanent damage.
Do not touch or move the keyboard.
Wait a full day to ensure everything
has dried out. Then, turn on the system. If you’re lucky it will work.
Cleaning the keyboard with rubbing alcohol or electronics
cleaner may be in order if you spilled a drink that will become
sticky after it dries. If you spilled water, don’t bother.
The principle about wet keyboards applies generally to computer
electronics. I’ve picked up computers left out in the rain or
snow, let them dry out, and used them without any ill
effects. Just dry them out completely before powering on!
displays are black boxes. The usual remedy is replacement. But verify
you don’t have
a device driver or software issue before junking your display. With
laptops you have to
buy a replacement screen for your specific laptop model and install
are generic video instructions for replacing a laptop display and here are
model-specific instructions. Anyone can successfully replace laptop
screens and keyboards — if
they download model-specific documentation and follow it.
Sometimes you’ll get a stuck pixel
on a LCD screen, a pixel that inaccurately remains an out-of-place
color like green or red. Use
a felt cloth to gently rub around the bad pixel in a circular motion.
If you can get the pixel to light properly, hold the pressure there for
a minute or two, and this often fixes it.
If your optical
drivedoesn’t work new
ones are cheap.
But first check all connectors, ensure the OS recognizes the device,
and that you have a working driver installed.
if the problem is sporadic? Try cleaning the drive with these
three cleaning techniques. Another possible cause is differing
between drives. It’s possible to write a disc on one system
and find another unable to read it. Determine if
you have a calibration difference by testing
multiple discs on several differentdrives.
You might find
that your drive works well with certain brands of disc media but not
with others. Media differences can
problems even with healthy optical
drives. Remember that there are many optical media standards
that you have to match them properly to the drives that use them. While
current drives support muliple
media standards, you can’t always mix all media in
all drives (DVD+R,
DVD-R, DVD+-R, DVD-RAM, Blu-ray, CD-RW, CD-ROM, etc).
What if your problem is a particular disc? Clean the disc by gently
rubbing it from the inside towards
the outer edge. Remove any fingerprints. Sometimes
wiping with a dab of distilled water will work. Other times, more
aggressive techniques are necessary. This article
has aprogressive list of steps you can work through to restore a
to a readable state. It includes my favorite — cleaning the disc with
toothpaste. Read the article before you try it.
if a CD or DVD gets stuck in the
drive? Look closely at
the drive face and you’ll see tiny hole. Stick a straight pin in there
andpush a lever that will
mechanically push out the tray. Do
this with the computer powered off
since it is solely a
easy to fix. Simply remove and
replace the bad memory stick. The problem is identifying that you have
a memory error, since many are transient
(sporadic). If you suspect a
memory problem,run an intensive memory checker utility like
or Hiren’s Boot CD.
You can also set the BIOS to quick-test
memory upon startup at the expense of a longer boot.
When you add memory into your computer, ensure
it’s seated correctly
before booting. If the memory is not inserted properly most
will beep and refuse to boot, telling you to
re-seat. Hopefully no damage resulted. After adding
memory, enter your BIOS configuration panels to ensure it’s
properly recognized before
booting all the way into your operating system.
things can go wrong with disks. If it’s a software problem, you can fix
If it’s a hardware problem, buy a new disk. Messing with faulty
disk hardware is not worth your time — with three exceptions:
- You need data only available from that disk (you didn’t make a
backup or it’s not current)
need to save your copy of Windows (if you lose your hard disk, you’ve
lost Windows and all your
- You need to save critical installed applications (you can’t
reinstall because you no longer have the install disks)
A fewgeneric rules of thumb:
- Never open the drive enclosure (it is sealed to remain dust free
and you can’t fix anything in there anyway)
- Download the disk drive manufacturer’s free drive-specific
diagnostic program. Some can mark off bad
disk sectors and even fix disk errors.
BIOS’s have drive diagnostic and test procedures. But often these are
as good as those you download from the drive manufacturer.
- As long as the drive still spins you can recover all or nearly
all of your data
can get your data back byspending money instead of time by
sending the drive to an expensive data recovery service. You can often
recover any data they can, but only if you
work slowly and conscientiously. This section tells you how.
Here are common disk symptoms and how to fix their underlying
“Operating System Not Found”
When booting your computer, you might get an error message like one of
- “Operating System Not Found”
- “No Operating System on Disk”
- “Missing Operating System”
- “Invalid Partition Table”
These are all software errors.
Your computer is telling you that the master boot
record and/or the partition
the disk are missing or corrupted. So it can not boot the operating
this by setting the computer to boot from CD/DVD prior
to hard disk, then booting and running a Live Linux CD/DVD.
fix a bad MBR or PT, run a program to rebuild this data. Boot a Live CD
Linux and select its option to rebuild the MBR and PT. Or use the
is a complete tutorial on it.
OS Detects the Drive But You Can’t
Access Your Data
Sometimes Windows knows a drive is present but
won’t let you use it, or it tells you the drive
needs to be formatted. Or maybe it just shows a blank drive that
contain any data. Or it won’t show its properties or let you
format it. Usually this means a software
You can fix
a filesystem to recover all or nearly
all of your data.
Here is a quick list of fix/recovery tools (with more here):
|FAT32, VFAT||TestDisk, Disk Digger,PCInspector|
File Recovery,Unstoppable Copier, Linux dosfsck utility
|NTFS||Lots of free and shareware toolshere,|
|ext2, ext3, ext4||Use built-in Linux utilities like fsck, e2fsck, ddrescue, etc.,TestDisk,DiskInternals|
It’s possible to have a hardware problem that shows the same
contacts on the underside of the drive are one cause. This
article has photos that lead you through how to clean the drive
contacts simply by rubbing them with a pencil eraser.
Drive is Not Detected At All
First make sure that drives have fully connected power and data
cables. You could get a variety of errors from this but “drive not
detected” is common. Check the data cable
connection to the motherboard as well as the side that connects to the
back of the drive.
Another cause of “drive not detected” problems is a failed logic
card on the drive. This is the
circuit board attached to the underside of the drive. The board
fail over time due to the heat coming off the drive and the
temperature differential from the powered-off state.
Take off the drive board and replace it with another. You can buy one
on the web or take one from another drive. The key to success is
that the logic board must be for the exact same drive.
If not, it will not work. Obviously,
you’ll only go to this trouble if you really need the data on the
drive and you have no backup!
Drive Makes Clicking Noises
This is the infamous Click Of Death.
Drives make clicking noises when they have tomove the disk arm
toretrieve data. The drive is not functioning properly and this
is its error correction procedure. Your
drive may fail very soon! Copy any data you need off there immediately. You may have limited
time so copy files in priority order.
If you can not get in to copy data off by normal means, here
is a procedure that extracts data from even the most recalcitrant
drives. It’s more detailed than I can describe here
but the key steps are:
- Hook up a second target drive to the controller (or you can use a
thumb drive as the target)
- Use the Ubuntu Rescue
Remix Live CD and its ddrescue command to copy the raw
drive image from the failing drive
- Make the target partition active so you can access your recovered
tries every trick in the book to read the data off the target drive,
bit-by-bit, regardless of what filesystems or partitions the drive
contains. It will even try to read the data backwards.
It’s very effective, but it might take many
hours or even days to get your data back. Like all the software in this
article it is free.
Drive is Not Spinning
the drive is not spinning, most people assume it is dead. Usually, but
not always. Sometimes you can get a dead drive working again by
it or dropping
the drive sometimes works. Be
certain you have no
alternatives before trying these methods because they may destroy your
drive! Prepare carefully in advance. You might only have one
chance to succeed and you don’t want
to blow it.
Add your tips to make this a better quick guide to fixing common
– – – – – – – – – – – – – – – – – – – – – –
Howard Fosdick (President, FCI) is an independent consultant who
databases and operating systems. He fixes old computers for fun and
charity. Read his other articles here.
|Laptop-Repair.Info||Covers all the basics|
|FixingMyComputer.com||Basic but comprehensive|
|Computer Repair with Diagnostics|
The Laptop Repair Workbook
flowcharts for diagnostic repair
|Post and review|