So yeah, I've been having issues with running games on my PC recently--it'll run fine for a minute or two, then the framerate starts chugging and doesn't stop. Every game I've tried running that does this has previously run completely fine on my machine. The problems persist on a fresh install of Windows 7, so maybe it's hardware related? Aside from that, I'm not really sure what the problem could be.
For reference, my PC is an ASUS G72GX notebook with 6 gigs of memory, a 2.53 GHz Core 2 Duo and a GeForce GTX 260M.