Codecs and media players are used for playing media (ie: movies and audio). They have nothing to do with a CD/DVD drives ability to read a disc.
Which OS are you using? Here is the fixit for XP:
http://support.microsoft.com/kb/314060
What is the drive status in Device Manager?
What type are the drives (ie: IDE or SATA)?
If they are IDE, are they sharing a cable or using different cables? Ensure the drives are jumpered properly (ie: Master, Slave, Cable Select). The drive connected on the end connector should be Master, and the drive connected to the middle connector will be Slave. Try a different cable or cables.
If they are SATA, no jumpers are needed. Try different cables.
Uninstall both drives in Device Manager, power off the computer, and disconnect one of the drives. Boot into Windows, and again check the drive status in Device Manager.