you tried a cleaneing cd. See if that can resolve the problem.
If does great if not could be that the actual player may be on the way out but first try getting cd cleaner that cleans the lense,
If you do need to get a new player the try gtting an external that is usb operated this will save you buying a new computer or if feel you know how to replace the drive the give is shot.
You can try click here for intranl and external players, alos ring to confirm