Ok, the laptop, purchased from MTU back when version 3 of Hoster was the latest (not sure of date) is a Durabook, model R15D. I'm using, now, Hoster version 3.321a. The cd/dvd drive (came installed, only one in it) is an Optiarc DVD/RW AD-5540A. Shows up under device manager and is functioning correctly with all programs except for Hoster. The driver is signed by Microsoft Windows Publisher and is version 5.1.2535.0.
I'm sure of the correct registry key (the same one Hoster tech was having me look at.
Screenshot shows directory. After I did a system restore to an earlier date, the upperfilters returned with some data, but no lowerfilters. Yes, I've removed the filters and restarted the computer on previous attempts.
Thanks for the help!