writes "According to Information Week, within hours of its wide availability Windows XP SP3 had drawn hundreds of complaints from users who claim the update is wreaking havoc on their computers. One user said in a Microsoft newsgroup: 'I downloaded and installed [the SP3] package for IT Professionals and Developers on one of my computers. Now I can't get the computer to boot. I don't think Microsoft should have made this a critical update.' Other sites including IT Wire are also reporting problems, which include include random reboots or the inability to boot at all."
Note that XP3 won't install on systems running beta IE8; and after a successful SP3 install users will no longer be able to downgrade from IE7 to IE6.