This sounds like one of the lasers is out of alignment and is actually raking along the disk, are there any scratches on the disks that go allthe way around the disk? This is indeed a big problem, but you should be able to play the other types of disks (other than the type that those games are on) since they use different motors and readers and such. Also: when did you last clean your PS2? It may just need a good cleaning.