Desktop dead after power cut

[singlecoil]

W7 computer was asleep while a power cut took place. Now the main switch won't latch. I've tried the lead and mains fuse in another piece of equipment and it's fine. I can't see a 'reset' button on the computer, any ideas?

[singlecoil]

I tried the simple cures suggested but unfortunately no joy, so I figured it was worth trying a new power supply. Fitted it this afternoon and to my surprise and delight it started up, the lights came on and it made its usual starting up noises. Only problem, no output to the monitor. Tried the d-sub cable and HDMI. Tried the monitor with a different computer, working fine.

Is it borked? Or is there something else I can try. It's no big deal if it has to be replaced but if I can get it working it would save me having to choose something else and going through all the choices such a task engenders.