Playstation 2 will not read the disc

My son's playstation 2 will take the disc but then goes right to a browser/system configuration page. When I choose browser it says reading disc... and stays like that for a long time. It is on a memory card page at this point. If I choose the memory slot it comes up with his latest game Lego Batman. I can't get it to do anything else. Help!! We have a sim one that is also doing the same thing. Do they need a severe cleaning (bought second hand)? The slim playstation would work if I cleaned the lens with alcohol. Thanks for your reply.