This may sound crazy, especially coming from someone without a PS2... however, I have heard from MANY people at work with PS2s. They have reported similiar problems and state simply inverting the PS2, to the upright position has solved some game play issues (specifically certain backed games.)

Just my $0.02.

-Jeremy
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"I'd like to move us right to Peter Gibbons. We had a chance to meet this young man, and boy that's just a straight shooter with upper management written all over him." - Bob Slydell (Office Space)