Have a plextor 712A and a Sony Crx300e. Microstudio does not detect or see either drive. Both drives are working and burn disk. Any one have any ideas what to check, Or why it does not see either drive?

I haven't use it in a couple months, and it is on seperate locked partition so no one can change anything.
Let me know what to do I will check back in in a few days thanks.
Peter