My PC is not reading CD's from a burner it used to read. I get pictures burned to CD for archival use, and now I have three CD's burned by the same machine, and I cannot read them. The shop checked a CD they had burned and it worked on their reader, but not on mine. What makes a CD reader not accept CD's it used to be able to read?

The first thing that comes to mind is another thread with something like this. Try going through Windows Explorer and ejecting the drive, then put the disc in and manually close the drive. That works for me, and works for the guy in the other thread. We haven't figured out what the error is though.

hmmmm, how do you eject the drive?

Just right click on the drive's icon and left click on eject