Diablo 2, help!
 

I have a burnt copy of the original D2, the play, install, and cinematics disc. When I try to install the expansion, which I recently purchased, It wont intstall all the way. First, I put in the "play" disc, as it says. Then, later on in the installation process, it say Please insert "play"disc, but it's already in there. What do I do?