Microsoft has posted the release candidate of Windows XP Service Pack 3 to its download site. The move marks the first opportunity for all users of the six-year-old operating system to try out its final upgrade. Previously, several thousand users were given access to test builds of SP3 only by Microsoft’s invitation. Update: I just installed the RC on my Windows XP MCE installation, and it all went fairly painless. I haven’t noticed anything radically different either yet.