Unable to access the bios

I am unable to access the bios; on startup I expected the key for this operation for this pc is the F10 key (setup). I tried many times to no avail, I tried other keys which are practiced on other brands of pc; always negative. I am doing so mainly to verify the order of sequences starting with floppy or CD, is now obviously impossible. If you find an explanation and a solution.

PC: HP Compaq Pentium IV

Did you locked the bios with a password?

I didn't remember if I have done that ever. If that's true then I do not know the password. How to recover from this?

Remove the battery and try to do a clear cmos.

What you are having usb or ps2 keyboard? Use ps2 because some systems don't accepts USB keyboard input.