I have recently built a computer from a Nvidia guide but when I built it, nothing would show up on the screen the mouse and keyboard didn't respond or show any lights. The rest of the computer powers on and everything is running as far as I can tell. I have replaced the motherboard but to no avail. Any way to get my computer running would be very helpful.

AMD X4 965 (CPU)
GIGABYTE GA-M68MT-S2P (motherboard)
CORSAIR 2x2GB 1333Mhz Dual Channel 240-pin DDR3 (RAM)
COOLER MASTER eXtreme Power Plus (Power Supply)
Caviar Blue Western Digital 320GB (Hard Drive)