only when I run a game with 3d graphics do I have this problem. my computor screen will have artifacts or will freeze completly and reboot on its own. it is the same with both cards. the first card is a 2yr old nvidia 6800ultra and the second is a brand new 6600le. I have updated to the most resent chipset drivers which souldn't make a difference since the first graphics card was running fine for two years one the old ones. so basicly i would guess that my agp slot on my board is no good or my ram may be bad. can someone help me please.

The 6600LE is a major downgrade from the 6800 Ultra. Have a look at these charts. You'll see the 6800 Ultra is MUCH better than the plain 6600. The LE (Light Edition) isn't shown, but it's a stripped down version of the 6600 with only 1/2 as many pipelines. http://en.wikipedia.org/wiki/GeForc... Your rebooting problem may be heat related, or it may be your PSU is failing.

Agreed.. check the temperatures of your case, video card and CPU. Might need to clean the case and all of the fans free from dust.