An AutoRun.inf file located in the root directory of a drive tells windows to automatically launch a program on that drive when the drive is first detected. Current versions of Windows often prompt to make sure that that is what the user really wants to run.
As an example an AutoRun.inf file may contain:
[AutoRun] Open=mowes.exe Icon=BRG_Drive.ico Label=The BRG Drive
The path is relative to the root directories. An AutoRun.inf file can be configured to launch a session of Business Rules!. This has been used for demonstrations of software, but could be useful in a number of situations.