Installshield does keep its installs in the registry, and a half way install can generally be cleaned up by deleting three major keys (though I can't remember which off the top of my head). I think this should only be done as a last resort however; so if you haven't tried it, I'd give the command line options a shot. Sometimes installing or uninstalling from the command line will work when launching the setup.exe doesn't (wierd that launching the uninstall from the command line works differently than from the gui, but it's one of the first thing Installsheild will tell you to do for a partial install). I believe the uninstall from the command line is setup.exe /x (or something close); you can get the command line options by typing setup.exe /? (or maybe it's -? or just ?, I don't remember off the top of my head). Sorry to be so vauge, but if this doesn't help and you're still having problems tomorrow, I'll break out the ol Installshield training manuals.