Here's a link that I found which has a copy of the instruction manuel. I tried to install the "C" drive and when I click on it it state that the drive does not exist. I can hear the hard drive running and the on light is lit. I've tried every step in the manuel also. Let me no what else you might be able to come up with. I've tried and downloaded the program that you suggested but, it's in German I guess? Anyway, the "C" hard drive icon did not appear on the desktop. Maybe this link may tell you more about the hard drive that I'm using.
http://homepages.tesco.net/~david.barraclough/atari/supra.htm
