Hi, Tim.
As the others have said, YOU know the make and model of your computer; we
don't. YOU have access to the manual for your computer; we don't. The
steps depend on the computer, not on which version of Windows (or other
operating system) you may be trying to run on it.
All we can do is guess, based on our knowledge of a few of the computers out
there. Most of them flash a very quick message when they are first turned
on - within the first 5 seconds of hitting the power switch. They usually
say something like, "To enter the BIOS, press F2". But others say to press
F10, or Del, or some other key.
We can't do better than that until you tell us what kind of computer you
have. But you'll save time if you look it up yourself in your computer
owner's manual.
RC