check to see if you have administrator rights on the computer. Don't know about vixen requirements, but some programs require administrator rights and this was written several years ago. Are you running Vixen 2.1 or 2.5 2.1 runs great on my Win7 x64, but 2.5 just loads then craps out whenever I try to do something with it. I only use 2.5 to look at downloaded sequences created with 2.5 so I just use on older XP box.