If your CD/DVD device is not detected anymore as a Source or Target in DiscWrite, but works properly in Windows, the Gear drivers (specific CD/DVD drivers used by DiscWrite to control the device) might be corrupted.
You can also get "Unable to open ASPI driver GEARASPI64.dll" error message.
Make sure it is listed in Windows Device Manager, in DVD/CD-ROM drives category
To completely uninstall the gear drivers :
Your CD/DVD device should now be detected by DiscWrite.