Re: something is wrong with my pc
Your Grapics card is dying, take it completely apart, remove all fans and connectors and pop it in the oven at 200 degrees F for 10 minutes. For a more detailed step by step, google "How to bake a Graphic card".
This is not a joke, this really works. 9/10 it a small solder connection has come loose due to heat, the oven will gently melt the solder and make a better connection. No more than 200 F though, not "C" can't emphasize that enough, and no longer than 10 minutes.
I have had this happen many times with an 8800 GTS, it will not work forever but you can do it several times, enough to get you by until you can get a new one.
EDIT: of course if its still under warranty, then go with that first lol.