Hi and welcome to RPC1,
in most cases the drive is not faulty and the problem is caused by the system (drivers, software, OS).
A good way to verify this is to create a DOS boot disk with CD-ROM support (on floppy or CD), start the system from this boot disk.
Then, insert an unprotected CD or DVD disk and read it under DOS using, for example, the DOS version of the freeware tool Nero CD/DVD speed (download from www.cdspeed2000.com
As an alternative, you can also start up the PC from a bootable CD/DVD - if this works, the drive is not defective.