Cant Get Computer To Power On

[decmatt]

Hi

I have an old Socket 478 PC, and I never got round to fixing it so thought I may aswell now. Basically, when i plug the power in, the green light on the motherboard turns on, however when I press the power button nothing happens, I dont know what the problem is. I have checked and double check the right connections from the case to the motherboard are right, I do not understand why it isnt powering on. Any ideas?

Thanks

 

[decmatt]

PSU seems to be working fine, does that mean dead MB?

 

[decmatt]

Carasik that CMOS thing worked a charm. Many thanks.

Thanks All!