MASSIVE FPS drop, drivers?

noticed a dramatic fps drop. The framerate used to average around 60 - 70 fps. Now its at 15 fps. The same's true for ALL games on my pc. (Its a private pc, only I use it).

I tried installing new drivers, reinstalling old drivers, using Driver Cleaner, trying everything that I found on google, nothing's worked. So is it a problem with my video/graphics card or is it something else? Is it a problem serious enough to require replacement?

Oh and, everything else runs fine, except games. I mean there is no other noticeable difference, no errors, Dreamscene and Aero run fine. I did get a BSOD related to a "nvlddmkm.sys", it happens quite often though. I've tried updating the file manually, it fixed the issue twice, but now, the third time this is happening, even this does not fix it. I'm really frustrated as hell and at my wit's end.

I've tried updating drivers of all my hardware too, nothing's working