title: Best way to make it so an exe can only be run once
body: <p>I've got a Visual Basic App that tends to get severely messed up if the installation runs more than once.  It seems the occasionally client mistakes the installer for the shortcut to it later on down the road, runs the installer again and it messes everything up.  I can't for the life of me figure out why so I decided the easiest way would be to make it so the exe could only be run once on a machine otherwise it would just end.  Any ideas?</p>