I have a CentOS 6.4 setup that was working yesterday.

AMD Phantom II 3.0ghz quad-core.

Today, I get the initial screen that tells me to hit <DEL> to enter setup.

After that, the screen goes blank.

I have tried rebooting about two dozen times. I have tried unplugging the HDDs, unplugging the USB printer. Have tried booting from DVD. No matter what I do, the results are the same.

I start hitting the del key right after I hit the on button. It simply does not work.

The keyboard is plugged in. I am sure of that.

Supposedly, the F3 or F4 key will unlock the BIOS (should not need to be unlocked.). I have tried those keys, they do nothing.

Any advice appreciated.

That looks bad. Re seat video card, memory, unplug everything (hdds etc). If you have onboar video and dedicated video card, unplug the dedicated one.

Not much info to go on. Was there an error message associated with message to enter the BIOS?

Is it a USB or PS/2 keyboard. Without knowing anything about your hardware one idea could be the CMOS battery died which caused the USB legacy setting to be reset. This would prevent a USB keyboard from accessing the BIOS.

Any beep codes ? Does it sound like it is doing something in the background, like accessing the HDD ? Does it always hang at the same time ?

I suspect the RAM or CPU. Take out the RAM sticks and try using only one at a time and see if it boots.

Remove the CMOS battery, go and make a coffee and drink it, take your time to let the CMOS drain. Replace the battery and try again. If it works you're lucky, if not your BIOS chip may be toast. Is it surface mount or sitting in a holder? If the latter, make sure it's pushed home tight.

I've got an HP ML370 G4 which powers on, the fans spin up and... nothing, no splash screen, Nix! I've removed memory, etc, and reconfigured it to a minimum system (removed all PCI cards, etc, and still nowt.) In my case, I'm 99% sure the System board is fried.

Like H TexMex H says, "any beep codes" which would indicate the BIOS still lived. Removing memory, leaving the minimum, normally forces the BIOS to display a message to let you know the config has changed. (Nope! None of that worked with my box.) >sigh<

Be lucky & Play Bonny!

Thanks for all the advice. But I decided to just replaced the motherboard.

I am now using a Gigabyte 78LTM-USB3. The new mobo only cost $45 at Microcenter - before $10 rebate. Plus, the new mobo has more memory slots, and USB3, and some other features. With HW so cheap these days, sometimes it is hardly worth trouble-shooting.

Replacing the mobo fixed the problem right away. I may try to revive the old mobo anyway, at some future date.