Lets try the old out of the case routine..
Disconnect everything off of the motherboard except the CPU, Heatsink and Fan.
Take the motherboard out of the case and lay it on a phone book or something non conductive.
Hook up the following items only.
Hook up the wire that comes from the power button on the front of the case to the correct header, See manual.
Hook up the the power supply to the motherboard.
Insert one stick of ram.
Insert the video card all the way.
Hook up the monitor.
Hook up power to computer.
Turn on the monitor.
Turn on computer.
You should have video on the monitor.
This sounds like a lot of work but it narrows down the devices to a few.
Try this and post back with the results, Relax and take your time...