video problems on Toshiba Laptop

[2cool4u]

I updated my video drivers recently on my Toshiba Satellite and tried to play counterstrike. Everything was fine but about 15 min into playing my FPS went from 60 to 30ish. Now whenever i play my fps sits at 60 for a min or two then drops to nothing above 40 adn when there is a graphic intense scene, me shooting @ someone close it goes to about 15-20 fps. I am not quite sure what happened but i reinstalled my old drivers and the same thing is happening again, which never happened before. Now when I play not only is my FPS really low, but there is a "tear" in the video which makes me wonder.

Specs:
512 ram
G-Force FX GO5200 (driver version 4.4.8.2)
80gb hd

any ideas on how to fix this would be great, i have tried turning vsync off and on and ithink that just made it worse.

Thanks