But with no OS mentioned and the hardware apparently in working order, my only suggestion is that you post in the Forum that matches your OS.
Bob
My son installed some old Windows games that were on a floppy into his computer and now it says the master boot record has been modified and the CD and CD/RW drives are not recognized by the system The BIOS still shows them, though. Any suggestions??

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic