This is an MSI ATA drive. If I insert a CD or DVD containing pdf files it is quite happy, and I can see the files, but if I insert a DVD containing mainly jpg files, or one with an iso file, or my Vista installation DVD then I get a message that there is no disc in the drive. File manager says the device is working correctly and it has the latest drivers.
This is a Ricoh MP9200A which was working correctly as I could see an iso file and it was happy if my Vista installation DVD was inserted. However, now it has a blank DVD RW in it and the disc light is on permanently and I cannot eject the disc using the button on the front or the eject button in Windows Explorer. This is still true even if I switch the computer off and then on again.
Thanks for the suggestion. Strangely, when I installed the first drive in a Vista computer, not the Win7 computer it was originally in, it was able to read all files. Both drives are now in a computer I am going to give to a charity which sends computers to African schools so I can forget about the problems I had.