Hi i have a compaq computer that is giving me a black screen and wont boot even with a bootable disk. any pointers?

To be able to better help you, describe what you do to get to the black screen. Describe any sounds, noises, from the compture or key presses that you do. It could be many things based on your description:

One possibility is bad disk, however it could be healing itself: Check: http://annoyances-resolved.blogspot....nk-screen.html