PC doesn't start on first push of power switch?

[IAmATeaf]

The system in my sig has over the last few weeks developed a fault whereby it won't start up on first push of the power switch on the front of the case.

EDIT: You normally have to push the switch 3-5 times before the thing will fire up.

I originally thought it was a dodgy switch but after testing it out over the weekend it looks like either a motherboard or PSU problem. Has this happened to anyone else and how do I go about diagnosing which is at fault. If it is the motherboard then I'll be mighty peeved as the things only just a year old, PSU I can live with replacing as I've had it now for good few years.

 

[Aero]

Just a thought have you tried a different psu on it from a mates machine perhaps?

Aero

 

[IAmATeaf]

Just a thought have you tried a different psu on it from a mates machine perhaps?

Aero

Nah, not tried anything as the spare PSU I had I sold and most of my friends now have lappies.

I think I'll pull the PSU this weekend and do the short pin 14 and 15 to see if it fires up straight away and monitor the voltages on it over the next few days. I'm just hoping it's the PSU as the mobos just gone out of warranty