This started like a typical job:

Customer calls, says PC will not switch on, no light on the tower, monitor says “no signal”

It all sounds like a power supply fault.

When I see the PC, I find out that the internal hardware was upgraded by a friend about 18 months beforehand.

And it looks like good quality equipment (Gigabyte motherboard, good power supply, kingston RAM, etc)

But the power button will not start the computer…

I connect a new power supply, but the PC still will not start… now thats unusual.

I check the power: yep 240 Volts is entering the power supply.

I short the “please start” pins on the power supply, and it starts normally

Good, the original power supply is ok.

Next: unplug all the peripherals, and reseat the RAM (only 1 stick of 2Gb)… but still no startup.

The only sign of life is when the power supply is switched on: the CPU fan moves a few millimeters, then stops.

Hmmm, Its unusual, but the motherboard (a Gigabyte ga-ma74gmt-s2) could have failed while under warranty.

So I take the PC back to the office for a more careful investigation.

• I remove the PSU, and use it to start my test PC.
• I remove the RAM, and use it in my test PC (without a problem)

I take a closer look at the motherboard, and the only thing I can do, is remove the AMD CPU, and see if I can find anything unusual

I don’t see any bent pins on the CPU, so I carefully put it back in its socket (I find it strande that AMD are still using “pins”, while Intel have moved to pads many years ago).

At this point, its looking a lot like a motherboard failure.

I decide to plug everything back, and try one more time.

I was so surprised when the PC started normally.

And I was left scratching my head, wondering what could have caused this.

In the end, the most likely suspect is some corrosion on one of the CPU pins. Removing and re-inserting the CPU was probably all it took to get all the electrical contacts working again.