Damn, I was just going to do my conjuring trick.
If DVD/CDs become ‘lost’, code 39 error “Windows cannot load the driver. The driver may be missing or corrupted (Code 39)”.
Go to Device Manager, uninstall CD & DVD drivers. Uninstall Primary and Secondary IDE channels under IDE/ATAPI Controllers - ignore requests to re-boot machine.
Go to Regedit, navigate to key HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\{4D36E965-E325-11CE-BFC1-08002BE10318}
Look for the key which refers to DVD/CD-ROM drives. Delete the subkey UpperFilters, also LowerFilters if it is present.
Re-boot the machine. All should now be well.