I have the above mentioned motherboard in a C2D E6400 system. The other day I went to pull out one of my hard drives(Sata 320GB Seagate) and an extra IDE DVD-ROM to throw in another PC.
I went to reboot my PC and nothing happened. No clicks/beeps/noises of any kind. So after messing with it I pulled it all apart, reseated the mobo, seated the 4 Ram sticks and processor, cleared CMOS by pulling the battery, and it fired up.
The problem then became the system hangs at the Gigabyte splash screen. I then tried resetting CMOS with the jumper, and it gave me the option to use the last known good boot config. It worked for one boot, and now it's stuck on the splash screen again. I've tried all of the steps above again and no luck.