Monitor / USB stopped working

So..

Last night my pc worked fine.

Since then it's not playing ball.

I have tested 3 different dvds/ 2 hdmi cables.
I have tested 2 power cords, removed the ram and tested those.
I have disconnected the disk drives, checked all the wires, applied a new layer of thermal paste , tried 2 different graphics cards, cleaned as much dust as I could nothing seems to work

I have a gtx 650to boost, corsair cx750m, and 8 core bulldozer cpu.

My USB ports are not working nor are my monitors.

I have no idea what to do now..

Anyhelp would be great