Hello,

My System Specs:
Pentium 4 3.2 Ghz
1 gig DDR II
GigaByte GA-8I945 GMF
LG DVD-RW
LG CD-RW
Western Digital 80GB
Maxtor 160GB
500W PSU
Windows XP SP2

Fans:
CPU Fan
Front Fan
Back Fan

My Problem:
For the last few weeks my computer suffers from Random Lock-ups.
I have made the following test:

1. Memtest-more than 3 passes.
2. HD Tests with the manufactor's diagnostic utilities: Data Lifeguard and Seatools.
3. I have tested the computer with only a single Memory chip at a time(3 Mem Chips), but the lockups still happen
4. I have made full formats on both hard drives and made a clean install of XP SP2
5. I have used Passmark BurnInTest, and couldn't finish the tests due to lockups.
6. I have opened the case in order to put a real Fan(big one) outside the case.

I am currently out of Ideas what can be the problem: Heat Related, PSU, CPU, Motherboard or something else.

are you getting BDODs?

Check your minidumps with M$ minidump checker.

No, I don't recieve BSODs.

When a random lockup happens the display freezes(you can see the last display), the sound freezes(you hear: trtrtrtrt ), the keyboard and mouse don't respond, Ctrl+alt+delete doesn't work, I can hear that the Hard Drive operation stops....

It happens completely in random operations and with different programs, it even happens when the computer is idle.