|(Sleep mode, while not generally recommended for desk tops, will not harm them. I use it to keep from having to reopen many things later or in the morning when I want to go back to something I'm working on)|
Did you try system recovery first?
If you mean that the CD drive does not read disk at start up, but was working normally before the problem, go into your BIOS settings and set the CD drive as first in boot order (or floppy first then CD second) with hard drive after so it will boot to recovery disk and reboot to it as needed until repair is done. Put the recovery CD in while in safe mode, and restart to the recovery disk.
If you have a non working CD drive, you will probably need to replace it before proceeding.