message appears saying reset machine

i have a problem. when i start my i book it trys to load and then the screen goes dark and the message appears saying reset machine. it tells me how i can do that. but when i reset it it does the same thing again. could it be that i need to reinstall the oparating system.
i bought a second hand mac ibook from the market a year ago.
i cant get on the system to try anything.

Sounds like you are getting a kernel panic.

Try booting from the install CD and run disk utility to check for and repair any permissions that are present.