Maximum PC

My PC will not recognize my monitor, keyboard (numlock, etc lights won't respond), mouse, and sound after a minor BIOS change. Most disturbingly, the HDD doesn't seem to be booting anything, either- it normally makes loud, distinct sounds upon startup, but is now near silent when I press the power button.

It was working just fine up to this point, here's the sequence of events that led up to the catastrophe...

"I almost never use this old machine for gaming anymore, I should quiet down the fans. Wasn't there a feature called AMD Cool n Quiet or something?"

I restart, go into the BIOS and enable Cool n Quiet. The system boots into Ubuntu without delay, web surf for a while, notice no change, and decide to set it back.

Here's the important part. I restart again, go back into the BIOS, reset C n' C back to normal, and then stupidly nudge up my RAM from "400" to "433" (I'm not an expert by any means). I'm 99% certain I didn't change anything else. When I save and exit, the system waits an unusually long time without any apparent action; I get impatient and hard shutdown it. When I turn it back on, the monitor, keyboard, HDD, etc do not respond.

I've unplugged and replugged pretty much everything to no avail, then checked inside; everything is dust free and no hardware components are warped or bulging. I have also tried booting an Ubuntu CD, that didn't work either. When I turn it on, the motherboard power light activates and the fans rev up. The HDD light in the front still blinks upon startup, just no noise.

Is my PC bricked? Help me out here please!

Locate the jumper for the CMOS, and reset it, that will remove your RAM Overclock setting, and reset everything back to factory. That should allow you to use the machine.

If you can't find the jumper, then pop out the quarter sized battery on the motherboard for about one minute and then replace it. The pc should boot into windows after that action.

Nasty

I'm typing this from the aformentioned PC; as you recommended, resetting the BIOS using the jumper pin and battery did the trick.

Thanks guys!