My new rig won't POST

[NiPNi]

I just put together a new computer looking like this:
- AMD XP2500+ Barton CPU
- Asus A7N8X Deluxe motherboard
- Chieftec Scorpio miditower case w/360W PSU
- Sapphire Radeon 9600 Pro Atlantis Fireblade ed.
- Corsair TWINX512 PC2700LL RAM
- GlacialTech Igloo Silent Breeze
Plus, of course, a few HDDs a DVD+/-RW drive, etc.

The problem is, when I turn it on, it shuts down again after 5 or 6 seconds. All fans start, the HDDs start spinning, but nothing shows up on the monitor and then it shuts down.

I have tried:
- Removing all drives
- Removing the graphics card
- Removing the RAM sticks
- Connecting a speaker to check for any messages, but it's nothing but silence there
- Resetting the BIOS
- Connecting a faster fan to the CPU fan header on the motherboard, as the Silent Breeze spins at only 1200rpm

No matter what I try, it's always the same: It starts up, runs for a few seconds and shuts down. No beep in the speaker, nothing on the monitor.

Any suggestions? This is SO annoying...

Edit: typo

 

[lobadobadingdong]

sounds like either a bad motherboard, or a bad power supply, do you have another power supply to test with?

 

[Unforgiven]

it could one of a few things i think....bad power supply, bad ram, or reset/power swithces from the case may not be hooked up properly to the board. also did you try removing the motherboard from the case? it could potentially be grounding out against the case, although that doesnt sound like what you have going on, its still something to consider.

 

[NiPNi]

I got a tip on a Norwegian forum, suggesting i should reattach the heatsink. I did, and now everything works! I never even though about that being the problem, but as it turned out, I had attached it the wrong way, so the heatsink wasn't even touching the CPU core.

Problem solved! Time for some serious benchmarking

 

[hagrin]

Interesting - I wouldn't have thought that although I also wouldn't put a heatsink on backwards.