I know you don't want to hear this, but I'd say it's time to reinstall Windows. :(

Seriously. Every six months. If you really want a super-stable studio computer, don't install anything at all on it that isn't specifically a tool you need to make music. Don't even surf the web or check email on it.

One option - if you've got lots of drive space, consider a dual-boot system - one boot into "studio mode", one boot into "life mode", where you do your gaming and web and email stuffs. I dual boot my studio computer between Windows XP (studio) and Linux (day job). A 200G drive is what, $150 these days? Definitely a worthwhile investment.