Back up cds will not load

[hen-rob]

Sorry if I am not putting all the information you need .
The error was that the back up copy(Harry Potter) would not fully load no error message came up it just stop at 40% on loading.This also happened on another friends computer with Medal of Honor with no error messsage.I think this may be to do with my back up copy's rather than there computers. Both back up copys work fine on my computer (pen 4-xp)