Whats wrong with my slim PS2 model SCPH-70012?

I have a ps2 slim model SCPH-70012, I got it from a friend that probably didnt take the best care of it. When I put a game, CD or DVD in it, it says "The disc could not be read". First off I need to know is this the same as a disc read error or something else? Second off is the lens adjustable at all and third could it have fallen or been thrown(my friend is a nutcase) and caused the lens to break or get knocked out of place? The reason I think it might have been thrown is because the fan frame was bent up a little bit and made a lot of noise but I fixed that already.
My email address is shrooman1984@hotmail.com if you want to email me. Any info reguarding the slim ps2 would help greatly, It seems theres no info anywhere on how to fix the slims, I hope it not cause its un fixable. Well thanks alot.