Member Avatar for krypto44

This is a custom machine... when i plug the power cord in, the green light on the mobo turns on to let me know theres power; which is good.

However, when i turn on the comp the fans light up and spin for a second or two then just stop. Nothing else happens after that. Its not the PSU because i have a spare and have checked both

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A few focused checks will usually find the cause of a machine that powers up for a second and then dies. As has described, this is most commonly a protective shutdown (PSU or motherboard detecting a short or overcurrent) or an immediate fault from a mis-installed component. 's suggestion to clear CMOS is valid, but combine that with a simple bench isolation procedure to narrow the problem quickly.

Bench-test checklist (minimal parts only): place the board on a nonconductive surface (cardboard), install CPU and cooler (properly seated), fit one known-good RAM stick in the recommended slot, connect the 24-pin ATX and the 4/8-pin CPU power, and start the board by shorting the front-panel power pins. Do not connect case front-panel wires, drives, or extra cards yet. If the system stays on, add one component at a time (second RAM stick, GPU, drive) until it fails — the last added item is likely the culprit. If it still shuts off immediately, try the spare PSU again or a verified-good unit under load, and inspect the board for stray screws, incorrect standoffs, or visible damage.

How to clear CMOS safely: unplug power, press and hold the case power button for 10 seconds to discharge residual power, then either remove the coin cell for about a minute or use the motherboard's CLEAR_CMOS jumper per the manual (short it for a few seconds). Replace battery/jumper, reconnect power and test. Clearing CMOS simply restores defaults — it will not harm hardware.

Extra checks and cautions: verify the CPU/socket pins for damage (pins may be on the CPU or in the socket depending on model), ensure the CPU fan is plugged into the CPU_FAN header, confirm all required GPU power connectors are attached, and listen for beep codes with a system speaker. If the board still shuts down on a minimal bench, suspect a defective motherboard or CPU and arrange component swap/RMA after documenting tests.

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Member Avatar for SnowDog

Has it worked at all or are you building it now?

Member Avatar for krypto44

building it now... specs are
m2n4 sli mobo
2x 1gb corsair xms2 RAM
amd athlon 4200+ x2
nvidia 7950gt
and 600w PSU

I moved the RAM around with no luck. Removed and replugged all the cables with no luck

Member Avatar for krypto44

* Have you reset CMOS


does that mean removing the MOBO battery

Member Avatar for SnowDog

That's one way, or some mobos have jumpers you can short to force reset to defaults.

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