Please check previous discussion on this page: Mafia 2 Save game download for pc - 100% completed mission - Part 1
Did you use any uninstaller for removing the program from your computer? I think that their might be some registry entry which might be conflicting with the game and causing the issue with the same. To work with the issue i will advise you to uninstall the program with the uninstaller Utility which removes the program completely from the system. Now again try to install the game and see whether this is working for you or not.