|Let's begin by determining whether the drive itself is faulty.|
Can you boot up into BIOS? Is the CDROM detected by the BIOS?
Will the tray open/close by pressing the appropriate button? Could there be a disk stuck inside? There should be a manual release hole in the front face of the drive. Use a straightened paperclip. push into the hole to click the manual tray release.
Have you opened the PC Case to check the power & Data cables to the drive?
Goin' Fishin' (Some day)