Hi DarkThunder,
The culprit is faulty memory. You can run memtest to stress the ram. If memtest reports the ram is faulty, ram is bad. However Memtest is not a perfect tool to test the memory as some faulty ram can pass memtest.
Suggestion
1. Check the temperature of the CPU and make sure that it is not overheat (ie temperature < 60C)
Make sure that the CPU fan works properly
2. Reseat the memory stick to another memory slot. Reseat video card as well.
3. Downclock the ram. Check to default setting if you video card is overclocked.
4. Clean the dust inside the computer case
5. Make sure that the ram is compatible to the motherboard
6. Check the bios setting about memory timing and make sure that it is on
For example : DIMM1 and DIMM2 do not have the same timing.
DIMM1: Corsair CMX512-3200C2 512 MB PC3200 DDR SDRAM (2.5-3-3-8 @ 200 MHz) (2.0-3-3-7 @ 166 MHz)
DIMM2: Corsair CMX512-3200C2 512 MB PC3200 DDR SDRAM (3.0-3-3-8 @ 200 MHz)
DIMM3: Corsair CMX512-3200C2 512 MB PC3200 DDR SDRAM (3.0-3-3-8 @ 200 MHz)
7. Make sure that your PSU have adequate power to drive all the hardware including USB devices
8. Run chkdsk /r at command prompt
9. Run 3DMark 2005 to test your video card
10. Upgrade BIOS
If it still crashes, diagnostic which memory stick is faulty
Take out one memory stick. If windows does not crash, the removed memory stick is faulty.
