Can you boot from a bootable factory CD (like windows XP) when the computer is first turned on?

If yes: It may be a software setting. Try these steps > http://www.tomshardware.com/forum/255409-45-working-drive-work

If no: It's probably a hardware issue, some of the older CD/DVD drives have a separate laser for each type. The motor that spins the disc operates at different speeds for each type of disc.. so motor could be failing too. Consider replacing the drive. Should be able to find them fairly cheap on the internets & they're easy to replace.