transfered library not working

My sister need a bigger hdd in her pc and I copied everything over that she needed but when it came to itunes I had to look up how to migrate her files. I found the solution on the apple website and followed the instructions using an external hdd. It seemed to all go well but it has been maybe four months and now my nephew tells me that ever since I swapped hdd's he has not been able to find his playlists and any new cd's he tries to rip to the library show no track length and will not play. I don't think I got rid of the old drive. Is there something I can do to fix this? Thank you