Did you buy the console used? If it was doing that when you bought it, than it may have a "Lost DVD Key." Xbox 360 DVD drives are "Married" to the motherboard of the console that they came with. If you simply replace a faulty drive with a working one, the console will not read game discs, only DVDs and CDs. You need to either repair the original drive, or swap it's controller board with a drive of the same model. (There are a few different drive variants, so you need a drive of the same model) If repairing the drive / putting it's controler board into an identicle drive doesn't solve your problem, there is really no possibility of regaining game functionality (unless the console is on a very old version of the dashboard, but I'll go into that more, if it's nessicary)