CPU fan turns on and off repeatedly without booting

bootcpufan

My PC has suddenly stopped starting up. On checking with case open, the CPU fan starts running when the power is turned on, but it stops after about 2-3 seconds, restarts again after about 2-3 seconds and the loop is repeated. There is no beep and nothing appears on the screen. On searching the internet, I found there could be several reasons for this. I tried removing hard-disk, CD drive, tightening connections etc but of no avial. I also tried using a new power supply but the response is the same.

Where could be the problem and how can it be solved? Thanks in advance.

Update:
The problem could not be corrected and I had to replace both the cpu and the motherboard.

Best Answer

Having checked a different known working power supply and without any other information, (do you have any LEDs on the board that blink when starting up?), I would suspect a failed motherboard component. To fully test the board remove everything except the CPU, one stick of RAM and the power connectors. If it starts like that try again with the others stick(s) of ram one at a time then all together. If it fails to start with any one stick then it's bad RAM. If you come up with anymore information we can work from there.

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