My desktop has this problem recently. When I tried to turn on the computer,
the first page of the booting process appear that shows
the DELL logo and F2 for setup and F12 for boot menu.

I hit F12 or F2 but there is no response. I believe my keyboard
is still functioning.

The screen just hangs there without going forward that allows me to
select to OS to boot, which is usually the case.

I inserted an installation into the disk drive and I could not boot from the DVD ROM. The screen just hang at F2-F12 page.

Does it mean that the motherboard of my desktop is gone ?
What can be possible cause of the problem ?

Thanks !

Try bashing on a few other keys, tab, escape etc. see if you can get past the pretty BIOS screen, and back the BIOS POST display, which may give you more information as to why the POST is hanging.

Failing that, google for the appropriate key to do so.

Try swapping the keyboard to another machine, or try a different keyboard, the BIOS could be sitting at the old "keyboard not present, press F1 to continue" error.

Thanks fukawi1 for the note.

I was able to solve the problem. The problem appeared when the USB cable connecting to a portable external drive was unplugged
when the system tried to boot from it. The BIOS crashed half way.
I opened the computer casing, took out the CMOS battery and then put it back in so that
BIOS is reset to its default value. And the computer is booting as usual.

Thanks.