This should work for you.
Search for the LT executable (aclt.exe) on the folder you have installed it, right click on it, select Properties, then Compatibility, and check mark the "XP compatibility" box, and also at the bottom on the same dialog check mark the "run as administrator" box.
Now you can run AutoCAD.
The first time you run you will see again a message that the program has issues, but just check mark the box on that message so that it won't appear the next time and click "run program".
Now every time you start AutoCAD you see a message saying your computer needs your permission to run this program, click "continue", and it runs. This message is normal on many programs for Vista, kind of exaggeration of the security features on Vista and it can be avoided by going to Control Panel and look for user account control and disable it. Microsoft of course does not recommend it, and it will show a little red icon on the task bar, but it will make Vista behave more like the way we wanted it, as long as we know we are not harming it's integrity with whatever we do on it, just like on XP. On XP, if you install something that is bad, the system will crash and you may be very frustrated getting it back to normal. On Vista it is much much harder to install something bad, but not impossible.
![Autodesk Design & Make Report](https://forums.autodesk.com/t5/image/serverpage/image-id/1350519iCB55845EBFC43016/image-size/large?v=v2&px=999" "Autodesk Design & Make Report")
