[SOLVED] Trying to start very old PC

[valkjrye]

I decided to try booting up an old PC that we brought from England to Australia. It's old enough that it has PS/2 ports for a keyboard and mouse. I connected a monitor via VGA and plugged in a power cord. Nothing happens when I press the power button. I don't see any I/O switch.
I don't know whether I'm missing something obvious, thought I may as well ask here. As far as I know, no components have been moved around, unplugged etc. It did turn on a year or so ago (while in Australia). I made sure all components were connected securely.

 

[SkyNetRising]

Did you check power switch on back of the PSU?
Did you check, if front panel power button is connected to appropriate contacts on motherboard?

 

[valkjrye]

Did you check power switch on back of the PSU?
Did you check, if front panel power button is connected to appropriate contacts on motherboard?

There's no power switch on the back of the PSU, and the power button seems connected fine.

 

[SkyNetRising]

You'd have to consult user manual of motherboard to make sure power button is connected correctly.

Anyway - next step would be removing PSU from the system and trying to start it manually by connecting green and black contact on PSU 24pin plug.