1) Review the documentation that came with your computer (also know as RTM -
read the manual - although some add an F between the T and M, so you can
guess what that means).
2) Watch the computer when it boots, all mine tell me which key to hit to
enter the BIOS Setup.
3) Call the manufacturer.
4) Go to the manufacturer's web site.
5) Find a qualified friend to assist you or lastly
6) Pay a qualified PC Technician.