I've been having problems with my disc drive. Specifically when trying to play downloaded games. The problems started with the free download bundled with Alice Madness Returns (American McGee's Alice). When I tried to play, it got throught the menus and initial cutscene with no problem. But it gave me the "disc unreadable" error as soon as it attempted to load the actual game.
Then, I tried playing Sonic Adventure. Again, it got through the intro video and menus just fine, but it froze on the loading screen of the main game.
I've already tried deleting the cache and reinstalling the games, to no avail.
Also, my disc drive is second-hand. Maybe that has something to do with it, but as far as I've played, it only has problems with the actual games. Game add-ons, save files and the trial for Sonic 4 ep. 2 work perfectly.
Thanks in advance!