Computer wont turn on.

[perseides]

I need help with my dad's computer. It is a self build simple work computer, gigabyte GA75M motherboard, with pentium G CPU, slotted with 8gb of kingston DDR3 ram.

The problem was that I could not switch on the computer at all. Pushing the on button does not switch on anything, no fan, no light, no error sound, nothing at all.

So far I tried:
1. Use a screwdriver to try switch it on manually from the motherboard power pins but its the same.

2. Take the whole thing out, and switching it to my own working power supply. (Connected only to the motherboard, 1 ram stick and cpu)

NADA.

How do i proceed? Is the motherboard dead?

Btw previously there had been same problems as the computer not switching on. Initially I thought it was the casing's on power switch. The computer just turned on after a while without any hardware changes.

 

[VirtualLarry]

So far I tried:
1. Use a screwdriver to try switch it on manually from the motherboard power pins but its the same.

Ok, that proves that the problem isn't the case's power switch.

2. Take the whole thing out, and switching it to my own working power supply. (Connected only to the motherboard, 1 ram stick and cpu)

So you took it out of the case, connected it with minimal components to a known-good PSU, and ... nothing?

I would try re-seating the RAM, and / or try swapping RAM. RAM is more likely to fail than the CPU, and sometimes, failing RAM will cause those symptoms. Other than that, it sounds like the board.

Btw previously there had been same problems as the computer not switching on. Initially I thought it was the casing's on power switch. The computer just turned on after a while without any hardware changes.

So, same problem, but intermittent? Could have been a failing PSU, which then totally failed and took the board and/or RAM (or maybe even CPU) with it.