For those trying to install the Police Quest games the on a modern PC, I have written new installers for the old Sierra DOS games. It will install your game and set it up to run automatically in DOSBox from Windows shortcut, just like any Windows game or program. Just download the right installer for your game. These installers do not include the games. You must own the games to install them.
The standard Vista warning for old games should be observed -- because of its limited write access, avoid installing in the %ProgramFiles% folder
("C:\Program Files" on most English systems or "C:\Program Files (x86)" on Win 64 systems) or you may have problems with not being able to save configuration changes or saving games.