Using ZoneAlarm Pro and AVG Free. I doubt I'd need them though, all you really need is a spyware sweep sometimes (Spybot S&D and Ad-Aware being good anti-spyware choices).
I once formated my HDD, reinstalled XP and installed all the latest updates, and 30 minutes later I had shortcuts to porn sites on my desktop.Terrible fail. You suck.
I didn't visit any other website than the Windows Update site.