Mcaffee pushed a virus profile update with a false positive in it which deletes a vital system file SVCHOST.EXE effectivly crippling thousands of PC's.
This effects Windows XP service pack 3 machines.
I have been personally affected by this 'glitch' and am still trying to recover from it. I have a thread in the computer issue section going if you want to check in.
Then again if you were affected by this chances are you wont be reading this today.
http://gizmodo.com/5521176/mcafee-up...s-xp-computers