New Asrock Z75 Pro3 wont boot

I've just built a new pc for my father in law, as his old one is... erm... old. lol

Asrock Z75 Pro3
Corsair 8GB DDR3 1600MHz
i5 3350P
HD 7770

But its not booting or showing anything on the screen. I took everything out, an just left the cpu\fan, power button and all the power connections for the board. When I turned it on, it done long beeps, which a quick google showed was no ram. So I put in 1 stick of ram, turned on again and got (I think) 5 short beeps, done a few searches on the net, which said no gfx card. I put this in and plugged in the extra power for it and turned it on, then nothing! The cpu, gfx and psu fans all spin, but that's it. No beeps, nothing on screen, just fans running and LED on front of pc.

I tried swapping the ram around, reseated cpu and tried the gfx card in the other slot, but same thing. No matter what I try I seem to hit a dead end once the gfx card is in.

I was wondering if maybe it's the PSU, as I used his old one, which I think is a 500w. His old pc, which he is now using again and gfx card is working in that. Is an old core 2 duo, so maybe he hasn't got enough power for gfx and the new cpu. Would taking my gfx card (HD 5670) round there be worth a try, or is the motherboard broken maybe?

Thanks in advance  

*update* just got him to check PSU, its a coolmaster 600w