[waynec]

The problem is that it just keeps vibrating once the disk is inserted into my Plextor drive. It speeds up, slows down, speeds up, etc. Finally it just keeps spinning and vibrating. It never gets to the point to be able to copy it or even "read" the contents.

MM did replace the first one with the problem. They said they first put it into their own computer and it worked OK before sending the replacement to me. The replacement disk had the same problem here.

Second, why would it work in my karaoke machine but not in the computer drive?

I have about 20 MM disks and only recently had this problem and only on these two (so far).