162 System options not set

This is a little confusing,when the computer starts up,you should press the designated key to enter bios setup,if you wait to long,then you are causing the system to bypass the function.

Remember to press the key when startup screen appears.

Of course I have tried that. I've held down the key before, during, and after. (At all different times, trying to catch the right time.) I've tried pushing the button up and down several times while it is trying to boot. By the time the screen comes up with the "Compaq Pesario" Logo, it has already started the memory count. I pulled the battery, to reset the bios, (I guess expecting that to cause some miracle to happen.)
Is my timing just off? or am I having an off day?
I've never had a hard time getting into any other bios, even if I don't know the key for a fact. I just try them all, and wind up getting in. It's been one of those weeks.....................

Try pressing the key.

Don't press it too many times. Press. Wait two seconds. Press again.

There was a time when every computer maker had their own magic key combination to get into the BIOS. Thinking back to those days you might try the key.

I'm having the same problem with a Compaq Presario 5152. It just refuses to let me access the bios/cmos. Again, Compaq says use the F10 key, but that does not allow access. It just runs the memory check and gives the Error 162 - System Options not set.
Any ideas out there??