Unplug power cord to your computer....
Then open your computer and carefully unplug both connectors to your CD player. To be really sure unplug where it connects to the motherboard too. Plugin-unplug a few times to rub off any oxidation and to reseat the connectors. Push them in all the way.
You prolly don't want to do the above. Save it for last resort
Should have ask how old the computer is, and when the interior (cabling) was last touched.