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I got a new case recently so I disassembled my working build and then transfered it to the new case. But now when the power button is pressed the all the fans (CPU, GPU) spin at full speed and the computer refuses to boot (no BIOS or display whatsoever)

I've reset the CMOS, checked the PSU with a multimeter, and have gone over the cable connections several times. I can't figure out why it isn't working.

The only thing that may have affected the transfer was that the computer sat disassembled for about a week before I had time to but it back together (I don't know how this could affect the booting sequence though)

Any ideas on how I can check get my PC to boot again? It's running Windows 7 on a Asus P5N-SLI motherboard.

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up vote 4 down vote accepted

Things to consider next:

  • Have you reseated all the RAM, CPU, adapters, cables, etc?
  • Have you stripped it down to just CPU to see if you get BIOS beeps for missing RAM?
  • Have you ensured there's nothing metallic under the motherboard (improper standoff, or a screw perhaps)?
  • Aside from the chassis itself, are all the other parts the exact same as before (like the PSU)?
  • Does it work when out of the chassis?
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Is the monitor working and plugged in? 9 times out of 10, it's something unplugged. – ChimneyImp May 26 '12 at 19:25
Videocard was bad. – Nick May 27 '12 at 16:27

Test outside the new case. Make sure your RAM is correctly seated and in the correct postions to boot. eg 1,3 or 2,4 etc.

Make sure that the motherboard is not grounding itself on the new case by touching it apart from on the screw mounts.

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Have you checked the 110/220 slider switch on the back of the power supply?

That one stumped me for a while once, now it's something I check every time.

Often, new power supplies in new cases are set at 220v, which presents a 20:1 stepdown instead of the expected 10:1. Thus, your maximum output is 120v@20:1 = 6v on the 12v rails, which is regulated to 5v on the 5v rails. Everything lights up, fans whirr, hard drives spin up – but the CPU won't fire over.

Just do not put the switch in 110v when you're overseas on a 220v circuit. That puts 24v on the 12v rails and 5v on the 5v rails (Yeah, done that too, it's only a small fire, trust me.)

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