No video output

[MrKosen]

I recently just purchased:
Gigabyte P55A-UD3 Motherboard
Intel Core i5-650 Clarkdale 3.2GHz
Corsair XMS3 4GB (2 x 2GB) 240-Pin DDR3
Using my old:
Nvidia 8600GT
550W PSU.

When I start up my computer I get one short beep, in the manual says normal start up noise. But I get no video output from my computer. Have tried different cables, and monitor. Recently purchased a new Geforce 9400 GT thinking my video card was shot. But still no video output.

Thank you for your help.

 

[EXCellR8]

have you tried seating the graphics card in the other PCIe slot?

 

[MrKosen]

I have tried the graphics card in the other PCIe slot. I recently just tried new cable and new monitor still no video output. Is there any chance even though everything seems to be powered up with the correct boot sounds that the PSU may be underpowered?