Is XP and Vista not safe enough, or what? I haven't had a virus in years, and my luck isn't the greatest.
Lol, its probably been your PC and others like it that have been spamming my ass off for the last few years without your knowlage. The most "effective/useful" viruses & exploits wont make the PC behave weirdly or perform badly because the criminals dont want it discovered. Windows has a history of being easily hijackable. Most notably windows 98/ME, 2k and XP (probably the most abused of them all!)
Hopefully now vista has adopted a few 'unix/linux-like' ideas to things like execution prevention/permissions and their own answer to "sudo" (run as admin Yes/No {LOL!!}) so hopefully these problems will be on the decline)
@gfk, if the update is failing, does it give a reason why or any clues why in the logs like access denied / timeouts etc. Maybe there are other servers you can set it to to update from :/ I have not had a problem with avg+vista (other than V7 wouldn't work)