Bad Preformance/Sound Problem

Hello!
Normally I like to solve my own issues, but I cant seem to fix this one, and hopefully someone here will have a solution. Anyway.

A few days ago, I started to get bad fps in any game. It gets slideshowy even on the lowest setting, I cant even run Hammer any more due to the lag. Now whats strange to me is the sound and audio glitches that come with it. In Bad Company the sound does that drill/drum repeating sound like if were about to have a BSoD. In Hammer my music on ITunes slows down and glitches but when I minimize Hammer, it plays normally. This seems to have started when I installed Civ 5 but I couldnt see that as a cause. Ive tried reinstalling directx, and sound/video drivers and a system restore.
I'd gladly reward some refined metal to anybody who can help me out with this.

My Specs:
AMD Phenom II 805
ASUS M4A89GTD-PRO/USB3
4gb Ram
GTX 260

Thanks

Thanks for the replies,

Duke:
Since its a program I never thought it could cause any harm to every game, but I will try uninstalling it to see if that helps.

Aly:
Will do, I haven't done it in ~2 months.

Game:
Unless Windows does it automatically I don't have any backups, just system restores (unless thats what you mean).

Nope, tried uninstalling Civ, defragging, cleaning all temp files, a system restore from weeks ago and still getting terrible performance and sound glitches. TF2 runs at ~17fps on all low, sound is still distorted and slowed while in hammer.

I think I'll just start backing up all important things and reformat.