I purchased a ASRock P43Twins1600 to put into my sisters computer. I took the old processor/heatsink out and put it in the new mob, put 2 sticks of ddr2 and hooked up power cords to mob + tryed all possible combos of power/reset buttons as per instruction booklet. The computer will startup run 10-13 seconds, shut off for about 5 seconds and then start up again. BTW tryed plugging in video card and nothing shows on the screen. I could use some help...
Its unlikely, but it could be a power supply issue. Try replacing it with a known working unit if you have one.
Besides that, I would check the standoffs. Try running the motherboard outside of the case. Lay it on the Anti-static bag and put in a video card to see if it'll boot. Also you may want to try re-seating the ram.
Sounds like an overheating issue to me, reseat the CPU and check the memory moduals, and make sure the power supply is working, these type of problems can be real easy or super hard to solve,so good luck.
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