While in DOS command prompt you can start an info screen project by typing in the command to run the DISPlayer.exe with a path to the info screen project .XDIS file. Here is an example of one such command on Windows Vista computers to start a project named 3ScenesSmall:
DISPlayer "C:\Users\<username>\Documents\Dynamic Info Screen\My Projects\3ScenesSmall\3ScenesSmall.xdis"

Note however that the DISPlayer's working directory is not added to the system path by default so the first thing you have to do after entering the DOS command prompt is to go to that directory. Here is the command to do that:
CD "C:\Program Files\XemiComputers\Dynamic Info Screen\Player"

If your system is 64bit then the command to change the directory is a little bit different:
CD "C:\Program Files (x86)\XemiComputers\Dynamic Info Screen\Player"

On a successful directory change your DOS prompt will look like this:
C:\Program Files\XemiComputers\Dynamic Info Screen\Player>

NOTE: If you just type in DISPlayer without a path to a .XDIS file then the DISPlayer's File Open dialog box will show up so you can select an info screen project to start.

Finally, you can skip changing the directory by typing the single long command as shown here:
"C:\Program Files\XemiComputers\Dynamic Info Screen\Player\DISPlayer" "C:\Users\<username>\Documents\Dynamic Info Screen\My Projects\3ScenesSmall\3ScenesSmall.xdis"

Instructions on this page are given for Windows Vista. They are relevant to other versions of Windows as well, but you can expect some small differences in folder paths.