PC hardware forum: Keyboard, mouse and monitor not working!

Hello! I got a new case and swapped all the components over the other day and everything worked fine. Then I went out, when i got back in and turned my computer on there was no power running to the keyboard or mouse and the monitor doesn't display anything ( although it knows something's there because it doesn't display the no signal dialogue box it would if there was nothing plugged in) . My system build is as follows.

Mobo- Asus P6X58D-E
Psu - Corsair CX 600
Processor -Intel core i7
System cooling - Corsair H50 hydro series
Graphics card - Radeon HD 5770
RAM - 3 x 2 GB DDR3 sticks.

Then just a 2 tb hard drive, wireless card...etc.

I'm running windows 8 compatibility mode at the moment but I've had this for months with no problems.

Any help on this would be greatly appreciated, from what I've read It's down to either a short motherboard, graphics card issues, or Psu problems, although all fans and power indicating lights come on when i turn the system on, it just doesn't beep, then turns itself off after 30 or so seconds. Any help would be greatly appreciated! Literally tearing my hair out here ( and with dreads that's no small feat)
Thanks!