Need a little help

[Grez]

I recently built my first comp and had it up and running just fine for a couple days. Was playing games and on interent all was doing good. I left for a two days so I shut down the comp. When I got back today I fired up the comp and it would start just fine, but the monitor just had a black screen. Tried rebooting and reconnecting everything in the back but still have the problem. My mouse and keyboard are wireless, but the main connector is a USB connection and it isn't lighting up when I start the comp, not sure if this is related. Just not sure what's happened since restarting my comp when it was just fine before.

Any help/ideas would be greatly appreciated

Main specs are Q6600 Quad, Asus P5N-E SLI mobo, 750 W PSU and EVGA 8800 GT- fan is running on this when I turn it on, so not sure if its a graphix problem with the monitor