hello every one, greetings.

my problem is that my computer freezes when i start any kind of 3D program such as google earth , or 3D MAX , or any 3D game such as gunner or pacific heroes ww2 , or any kind of 3D screen testing, i increased the rams up to 1g , and i also i plugged display card with 256 speed , but it still freezes, sometimes as soon as the program begins or after 10 or 15 min. but after i connect a display card it freezes after 45min. i formatted million times i have changed many virus programs such as Norton internet security 2007 and trend micro and bullwatch, and kaspersky, but the same problem, one time i installed Norton internet security2006 and i made a full system scan it detects one virus and delete it and the problem was gone, but when i had to change the Norton from 2006 to 2007 because it was an old version the problem came again.
so please help me, is it rams problem, or virus problem or ms dos's.
please I'm fed up , any one ...... help!!! i'm realy appreciated for your kind cooperation.
thanks. and truly yours

An over-heating graphics subsystem could result in system lock-ups...whether integrated on the motherboard or on an adapter card.

3D operations can cause the video GPU to heat-up extremely fast. Depending on the cooling system, I've seen GPUs heat up +40C above "typical" in under 10 seconds when such applications are run. For example, a GPU running at 35C would increase to 75C within moments after the 3D application was started.

Remember too, that video operations often heavily involve the CPU in addition to the GPU, and the CPU and/or system RAM could be over-heating as well.

Use a temperature and fan monitoring program to see what's going on. Which one you use could depend on whether you're running Intel or AMD, or ATI v. nVidia, and so on. Some motherboards support such monitoring, others don't.

Perform standard cooling subsystem checks...clean the heatsink, fans, and vents, check fan speeds, re-apply heat-sink(s) paste if needed etc.

If you need detailed info about such procedures, let us know. A lot of that kind of info is available in other HWA threads and on the internet.

edit-add a few more details