Games all of the sudden lagging?

[Zifuzo]

Hey, whenever I usually play games I get a very high framerate. All of the sudden this morning when I logged onto my PC every game is suddenly lagging like crazy, only FPS lag. I can't even play the game on the lowest possible settings without getting tons of lag. I don't know if its heat or some kind of malware/virus slowing me down. Or one of my programs. Please help!
PC SPECS:

CPU: Intel Core-i5-3330 3.0GHz
RAM: 8GB Corsair Vengeance 1600MHz
GPU: NVIDIA GTX 660
HDD: WD Caviar Blue 1TB
OS: Windows 7 Home Premium

 

[Risteh]

I had a problem similar to this once. Try pressing the reset button (while it's on) on your PC case if it has one. If that doesn't work then try to do a full virus scan with something like AVG Anti-virus.

 

[cats_Paw]

Well, If its hardware (unlikely) check the temperatures on your CPU and GPU. Also, what PSU you have?
Was there a power outage at your home before this lag started? Try to think what did you change from the day before it started lagging (did you install a new program?).

 

[kau1997]

Could also be a driver issue, is you native monitor resolution normal?