Playstation 2 Slimline Problems?

My PS2 (Slimline) has disc reading problems. It won't play Midnight Club 3 Dub Edition Remix. When I put in the game, it says the disc could not be read. I've already cleaned the disc and the lens in the PS2 (Please don't suggest one of these, already tried it). My system also has problems reading GTA Vice City, VC works but has problems loading. Anybody got suggestions?