Computer restart when 3D program running

[cyc85]

Sometime when i just open google earth,my pc will restart. When i was playing Dota game then it also suddenly restart. No minidump file created. So i cannot find the problem. Any idea why this happening???

Pentium 4, 3Ghz
RAM 1G
Ati Radeon 9600

p/s:

-my cpu didnt overheat after i checked with speedfan.
-recently i just bought a new ram(512mb)
-ram no error after i test with memtest86

 

[dopefisher]

Do you have the latest version of directx installed? Try running directx diagnostics program by clicking start menu ---> run ---> type in dxdiag.exe and hit enter. Go over to the video tab and run the direct3d test. report your findings here.