It's freeware, and what a wonderful product! A pgn viewer means Portable Game Notation Viewer.
What it does is take the notation of a chess game in a .pgn or .txt file, and show you each move on a chess board.
DROP-DOWN LISTHere is a dropdown list with some pgn files, using the LT PGN viewer. If you click on a selection, it should open up a window showing the game.
You can find pgn files at this really great resource: http://www.pgnmentor.com/files.html
Thank you for visiting. Hope you enjoy!