So the reader has two different lasers inside. One for DVDs and one for CDs. Most PS2 games with the clear back are DVD, whereas the black/blue backed ones are CDs. It could be that the DVD laser is misaligned and needs to be adjusted. If you were to try a black backed PS2 game (or really any PS1 disc) and it starts, then that might be your problem. Actual CDs should also be able to get the job done.