How do I use WinBoard as an external viewer for PGN files with the MS Windows File Manager or Explorer?
WinBoard sets this up automatically when you install it, except on old versions of Windows NT (prior to 4.0). On Windows NT 3.51 or earlier, go to the File Manager, click on the File menu, select Associate, enter “pgn” as the extension, and use the Browse button to find your copy of WinBoard and set up the association.