tried failsafe and expert?

tried testcd ?

In rare cases, linux won't work with your processor / mb. If nothing else works, try downloading something like the debian install CD ( 30 mb ) and see if that boots. It may be a bug in the way the kernel is configured.

Is your cpu overclocked? Check in the bios, if you have plug&play OS turn it off. If you have an OS selection, change it to UNIX ( newer MB's ).