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PC wont power on  - fan spin for 2 seconds then nothing happens

auraorange asked
I have a friends PC, when you press the power button the fans spin then they stop again.

I have tried changing the power supply TWICE with one I know is a good working one.

The CPU fan was really badly clogged with dirt and dust so ive cleaned all that out

Hardware wise it's a 3ghz P4 processor, 2 * 512 ddr memory, cd drives and 2 sata drives, a P4M-915G/PDI motherboard.

I have also taken out all PCI cards, graphics card, unplugged the hard drives, re seated the memory, cleaned the CPU etc.

If I actually hold the power button in the pc fans stay on but ive only held it in for 3-5 seconds as I dont want to damage anything else.  So it could be the power button or maybe the motherboard??

The problem is there is no reset button so I cant rewire the power on switch to effectively power up the PC using the reset switch unless I swap everything over to another case.

Does anyone have any suggestions before I start completely rebuilding and swapped casec etc??


Watch Question

The power switch is a momentary contact switch. For the behavior you describe, it would have to stick in the depressed position. To rule out power switch, disconnect its leads from motherboard header and use a jumper (borrow one from a drive) to power up PC. Touch pins with jumper and remove as soon as CPU fan starts.

If that does not help, disconnect all drives, remove all cards except video card, and try to power on with a minimal system.

Also inspect capacitors on motherboard for any signs of swelling or leakage. Pay special attention to those around CPU socket.
Forrest BurrisSystems Engineer
Nothing to do with the power switch or the power supply. The power switch wouldn't work at all if it was bad. The PS you've changed twice and it still happens. Since it doesn't spin up, stay up, but not show any video, beeps or anything, it's not the processor. Your motherboard is bad. Replace it and you'll be good.


Ok ive just swapped the CPU, mobo, RAM and powersupply over to a new tower and still have the same problem so yes it appears the motherboard must be bad, that isnt too much of a problem except I cant find another one of those boards for love nor money.

I think its an asus P4M-915G/PD1  (not PDI it's PD1)  note in my original post i put I instead of 1

If you know anyone who specialises in motherboard supply then i'd be greatfull. (i'm located in UK)

I'd say the motherboard as well.

Did you just air-dust the CPU fan? Or the whole insides of the computer? I'd air-dust the whole thing.
As for motherboard supply, I like pricewatch a lot. They have listings for international sales now too.


I searched that model number though, and nothing showed up.

As you may have gathered, I also suspected motherboard but wanted to rule out some other possibilities.

Any reason why you need an identical motherboard? There are a number of socket 775 mobos compatible with your CPU. eBay will be your best bet for an exact match. Here's a board that will accept both CPU and existing RAM. It is likely available on that side of the pond as well.

Is this what mobo looks lik?. It's closest model number I could find on FIC web site.


Will YES thats the board i've just sent them an email

I've been on pc world, ebay, ebuyer, dabs, and can not find the board anywhere.

The main reason i'd prefer the same board is id not have to mess with the installation of windows.  My friend is also making maximum use of all USB, sata, IDE, power, fan outlets on the board etc so it just would make life a lot easier to change for the same board.

Anyway i'd better close this question now and get some sleep

Thank you all very much for the help and advice / time spent.


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