I had the same problem with mine. Some discs it would detect and others it wouldn't. What I discovered is that the center post which holds the disc in the machine only holds some discs securely. Other discs it does not which allows the dvd to free spin and not be read. I took a small piece of electrical tape and stuck it on the edge of the hole of the dvd I knew it wouldn't read...and it then worked. I don't know how to fix it and I am trying to find a site now that has parts. I am hoping that they have a center post that has a better clip to hold all dvd's in place. Does this answer your question?
bpinkc, February 2005