Ummm....not sure, but I thought that I had heard there was a problem with the Orion and the drivers and Ascom or something. Have you tried Orion's web site for updates. I think it's
www.telescope.com but not sure on that either. Also, I would upgrade to XP, just to tick Vista off!!
I'll ask through our Society, think they had this problem, will take a couple of days though.
