help no screen on startup

Need more details!

If the machine is older than 4 years old, a PRAM battery or capacitor may be to be blame.

If the machine is under four years old, is it a notebook or a desktop with a built-in display, or a desktop with a separate display?

Identify your Mac here:

https://discussions.apple.com/docs/DOC-6413

Note: in order to be able to run a Classic operating system, you need a Mac that is from early 2006 or earlier. If it is newer, you posted to the wrong forum for future help, but I will gladly help you from this point once I know what you have.

Lastly when you say "no screen" is the display black, and no power light on the sleep light, or sound from the computer, or is the display black and you have either sound or light indications from the computer?