1. Download MIM as usual, but uncheck the 'run' box on the 'finish' screen.
2. Go to the MIM3207 directory, right-click on mim3207.exe.
3. Choose the properties menu item.
4. Click on the second tab called 'compatibility'.
5. Check the box and choose Windows XP service pack 2 from the menu immediately below.
6. Check 'run as administrator' at the bottom.
7. After clicking on the shortcut to start MIM, Vista presents a dialog box saying that an unidentified program wishes to access the computer, and asks you to approve it. Click 'yes' (of course!)