thanks for the suggestion...however it didn't help. I found instmsiw.exe on the cd (no msi.exe) and installed it successfully, but got the same error on installation of Inventor. Even after I repair it and it says it was installed successfully, if I hover the mouse over the Inventor icon on the setup menu, it says that Inventor is not installed. It's been awhile, but if memory serves, when I first tried to install it, I aborted (legally by hitting cancel or something) for a reason that I can't recall, and then when I tried again I got this error. For that reason I've been assuming it had something to do with some remnant of the original install that it doesn't like. However I've uninstalled completely and gone throught the registry and deleted all "inventor" tags, so I don't know what to do at this point.