The other day i downloaded something from a site which is safe according to SiteAdviser. I scanned the download and it came back clean (AVG). But shortly after running the download (an installer for a plugin for iTunes) I noticed that my web browsers are messed up. Both Firefox and Opera will just close down abour 20 seconds after I open them, totally regadless of what website I'm at. Internet explorer seems okay at first, but occasionally it will freeze up. Could take 5 minutes, could take half an hour.

So if anyone has any idea, I would greatly appreciate any input. Thank You.