I need help with backing up my son PS2 games?

my son has a bad habbit , he "forgets" to put his ps2 games back in the cases, as a result he has badly damaged a few, as i refuse to buy him replacements can anybody tell me the best way (any software I can buy) to backup his games which will work on his ps2, I have tried just copying them but they will not work in the ps2 console , it keeps coming up with "no data", please please help

Dave
October 2007