(from CNET)

McAfee's popular antivirus software broke down on Wednesday, causing Windows XP computers to have networking problems or repeatedly reboot.
By midday Wednesday, reports began to indicate just how widespread and damaging the McAfee update was.
The University of Michigan's medical school reported that 8,000 of its 25,000 computers crashed. Police in Lexington, Ky., resorted to hand-writing reports, and turned off their patrol car terminals as a precaution. Some jails cancelled visitation.
Early reports attributed the widespread problems to a routine McAfee update that caused computers with Microsoft's Service Pack 3 installed to incorrectly identify a legitimate operating system component as containing a virus.
The update effectively confused the PC's immune system, causing it to attack legitimate operating system processes in the same way that some diseases can cause the human immune system to turn inward.
A McAfee representative confirmed the problem to CNET, and said the buggy update code had been removed from the company's servers and that a fixed version would be made available shortly.
"McAfee is aware that a number of customers have incurred a false-positive error due to incorrect malware alerts on Wednesday, April 21. The problem occurs with the 5958 virus definition file (DAT) that was released on April 21" at 6 a.m. PT, the company said in a statement.
A report at the Internet Storm Center said the McAfee update registered a false positive and flagged the Windows file svchost.exe as a virus.
The update did not seem to cripple computers running Windows Vista or Windows 7.
Compounding what seems to be a day of snafus for the Santa Clara, Calif.-based company was that it initially directed affected users to download a file from its support site. But after tens of thousands of irate users flooded into the forums, the site abruptly went offline, and began to return an error message.
McAfee has posted a Web page on a separate site with detailed instructions on how to fix XP computers that have been crashing because of Wednesday's update. It recommends manually downloading and installing an "EXTRA.DAT" file, and then restore files that have been incorrectly quarantined.
But that option requires a least a modest amount of technical ability, and as of 1 p.m. PDT, the company had not offered a better way. "McAfee is continuing to work on an automated solution," the page said.

Every computer we've bought has had McAfee installed by default.. On the first one that had XP my parents used it for a while and then decided to switch away from it (they didn't want to renew their subscription). As soon as they didn't renew, their computer was hit with a bad virus. They still use the same computer and there is still crap left over from that virus (which was years ago).

I've used a lot of AV programs in my past, lol. From the start: Norton, AVG, McAfee, McAfee (renewed sub, was because my mom bought it again), Avast, Avira, Avast again. lol.

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Wow, whats funny is that I stopped in the middle of this post and downloaded the giveawayoftheday xDD. After I installed it, I was like "Ok! Back to posting!" Lol.