After tweaking the voltages on my proc and memory (very minor, 1 increment), my mobo failed to do anything on start up. I didn't even get the gigabyte splash screen with the option to enter bios. My board did not come with a cmos jumper so I used a headphone plug to make the connection. When I booted up I got a CMOS checksum error - Defaults loaded, with the option of F1 to continue and Del to enter setup.
The problem is neither one works. I press the buttons and nothing happens. Its not the keyboard (I'm typing with it now on a different machine). The common solution is change the battery which I intend to do tomorrow. Despite the battery problem (if that is the problem) I can't find a solution to the lack of response of the system when I press the buttons. I have tried multiple working keyboards.
Literally turn the PSU off, and unplug the power from the PSU.
Then short the CMOS jumper closed again as you did before, for a few seconds. Worth a shot. As you've tried multiple keyboards, I won't suggest checking the connection. Did you make any other changes that a CMOS clear would not revert?
I did have the psu switched off and unplugged. I even tried taking the battery out for a couple minutes. Still the same problem. I'm going to Radio Shack today to get a new battery. I'll report back tonight. If anyone else has experience with this I would love to hear about it.