Double disc games

[dalecrewe]

hi. I can't get the 2nd disc of my doulbe disc games to read.
if I use the original to get into the 2nd disc and then save it and start it againg using the 2nd disc copy, it'll work but when i get to the point in the game that says insert disc 2
it either won't read it or says incorrect dics even though it worked before.
help!