[SOLVED] Fans spin, lights on, but no boot

[Aldebaraan]

I was using a old computer to listen to music. After a hour or two i turned the monitor on and noticed that the there was no image. I thought that it had went into sleep mode so i turned off the psu and started it again. But this time it didn't boot up.

Extra details:

1. The cpu cooler spins for half a second then stops.
2. the mobo light turns on when the psu is powered.
3. It's a old PC. I don't know if it's related to the mobo or the psu but when it was working after powered it turned on automatically, made a post sound, then needed to be turned on again from the power button.
4. I tried another psu on it. Now the cpu fan spins now stop but it doesn't boot. Mobo light also turn on.
5. It doesn't have a gpu. It's integrated in the cpu.
6. I already tried re-seating all the cables.

 

[Paperdoc]

Check carefully the cable from the CPU cooling fan to the mobo CPU_FAN header. There MAY be a poor connection between the connector and the header pins, especial for Pin #3. That is the one that carries the fan's speed signal back to the mobo. On many mobos that CPU cooler speed is monitored carefully for failure (i.e., no speed signal). IF the CPU_FAN header does not get a fan speed immediately on start-up, it may refuse to allow the system to boot, believing that there is NO CPU cooling and it must prevent disastrous overheating.

Simply unplug the cable from that header and re-plug several times. This action MAY clean off a small oxide coating on the metal contacts. While you do that, look at the connector closely in case there's a bad or broken connection in the wires.

 

[Aldebaraan]

Check carefully the cable from the CPU cooling fan to the mobo CPU_FAN header. There MAY be a poor connection between the connector and the header pins, especial for Pin #3. That is the one that carries the fan's speed signal back to the mobo. On many mobos that CPU cooler speed is monitored carefully for failure (i.e., no speed signal). IF the CPU_FAN header does not get a fan speed immediately on start-up, it may refuse to allow the system to boot, believing that there is NO CPU cooling and it must prevent disastrous overheating.

Simply unplug the cable from that header and re-plug several times. This action MAY clean off a small oxide coating on the metal contacts. While you do that, look at the connector closely in case there's a bad or broken connection in the wires.

That worked. Thanks!

 

[Paperdoc]

You're welcome, and thanks for Best Solution.