Question : Problem: computer restarts suddenly without any apparent reason

hello,

I'm running a custom built P4 which started to restart several times without any reason. I tried everything I knew and nothing would do. I updated almost every driver (some of them I can't find....), I cleaned all the fans, made tests to see if it was due to an overheat. I tried to find information in the event log, but nothing in there. I ran a memtest, didn't find errors. Thought it was Vista, I formatted my HD and reinstalled XP, it did not work. I ran virus tests, I ran the W32.Blaster.worm removal tool, didn't find anything.

I still think it may be related to faulty memory sticks, because I don't trust that memtest program... or it could be any other hardware device...

Here's my config:
Intel P4 3.0Ghz (not overcloaked)
2X512 MB RAM 400Mhz Kingston running in dual channel
AGP Radeon 9550 graphics card (256MB)
Dynex DX-SC51 5.1 sound card
D-Link DFE-530TX PCI fast ethernet adapter (rev.A)
Maxtor 7Y250P0 Hard Drive
BENQ dvd dual DW1610 cd/dvd drive

What I think it could be is a conflict between the D-Link card and the ethernet controler on the motherboard, which I'm not able to install correctly.

Any idea of why the computer could restart? Oh and when it does restart, it shuts down, restarts, then doesn't last for more than a minute and restarts again. It does so forever, I have to close the computer myself and wait.

Answer : Problem: computer restarts suddenly without any apparent reason

>>   I don't trust that memtest program   <<   that's odd - everybodey regards it as the best; but you can run windiag instead :   http://oca.microsoft.com/en/windiag.asp

>>  a conflict between the D-Link card and the ethernet controler on the motherboard, which I'm not able to install correctly.    <<   then test if it restarts with the card removed, and the on-board disabled.

Basically, it can be due to almost anything hard ; you can diagnose by running with devices disconnected, or disabled in the bios.
Good candidates are PS, and mobo - btw; did you test with another disk drive too?