You should consider moving to Linux; it'd be hard to get a virus if you tried. (Alright, maybe you could, but you'd have to be an idiot to get one usually). Not to mention a huge list of pluses over Windows... but I won't post them here.
By the way, if you're not comfortable uninstalling your Windows to make way for Linux, there's a ton of tutorials for partitioning your HD and dual-booting. Or you can stick it on a crappy old machine to test it out. Or you can use a live disc.