losing 15-30 fps while playing COD4

It just started doing this a few days ago.actually it started when i left the computer on for about 18hours straight when i thought i shut i down.. anyways I can load up COD4 play for a few hours then all of a sudden i start losing FPS. Nomally i can hold a constant 60 fps through out playing for hours on end no problems. I checked my temps a sec ago and it 77c max while playing. So temp shouldnt be the problem(unless i damaged the card keeping in on for 18hrs). any ideas of what could be the cause of the slow downs? could it be it just needs a cleaning? keep im mind i had powermizer off forever since it stopped the screen artifacting . i fear the worst.

thanks for any help.

edit- model is 7805u

 

Different drivers can suddenly stop responding and then start working again. That messed me up for the longest time because I wouldn't see the yellow caution sign. What Drivers are you currently using?

 

I would recommend you keep your temperatures below 75 degrees. I usually like to keep my temperatures around 70-72 degrees max. If I let my temperatures get too high, I would experience slowdowns too. Try this if you aren't already doing it: Lift your laptop from whatever surface your playing on about 2 inches with a paper or cardboard box set in the front of the laptop and the back. Letting some air pass below your machine helps greatly in keeping your temps down. I overclock my machine for hours and hours on end with no problems. Hope this helped

 

im currentlly useing d0x 185.85. and have been since i got the 7805u. its a weird problem because if reboot when i notice the slow downs i will gain those lost fps back again for a bit. and A.F i have it lifted up with a fan blowing air under at all times.