Use device manager to uninstall the drivers for the drive, and windows should automatically detect the device. If it doesnt work, go on the Imation website and look up the drivers for your specific drive.
I don't know. I made a few more enquiries and someone sent me what they called a 'fix' to correct the corruption in the registry which causes the syndrome of disappearing cdrom drives. It was sent in a zip file which I unzipped, clicked on and my drives were back. It was a script but I don't know what the script actually was.