Alright well you are a little vague there, are you trying to install windows? If so then go into the BIOS by pressing a key (it usually says when u start the computer what key to enter setup or something along those lines). Find a place where it says boot order in the BIOS, you may have to look around if you are unfamiliar with your BIOS. Set the first device to boot to be your cd drive, then save and reboot your comp with the cd in and it will go into the setup.
If after you've done that and it doesnt boot then it means somethings wrong with the drive, make sure its plugged in right.