This is going to sound incredibly freetarded but here goes.
Last week I updated uTorrent as I posted in the bitch about GAF thread, and it installed a bunch of malware. Not even like spamware, actual malevolent software. Luckily my work had been meaning to upgrade my laptop to Ubuntu so I just did that on Monday.
Ubuntu by default kinda sucks, but Gnome Shell makes it much better. Love this thing now and I don't have to worry about that virus crap anymore.

Gaming though...

I want my suped up HTPC to be Linux, it'll run Dolphin well enough, but not normal PC games...
Anyways my advice would be to install Linux if you don't PC game, otherwise... backup your important files and reinstall Windows. The really nasty stuff will never really be gone. Even after running full scans with both Security Essentials and CCleaner that crap wasn't completely deleted.