Pgn file can be seen by your pgn viewer. If you have Vista you may have to download the Vista link page for instructions on how to change the file associated to a pgn viewer like chessbase. Note that Chessmaster will not open pgn annotated games, best to try cblight. Safari browser may not work.
This is the address for Vista change file assocaition
http://www.mydigitallife.info/2008/06/20/how-to-edit-or-change-file-type-or-extension-associations-default-programs-in-windows-vista/
Annotated Games in PGN format Games through a Web pgn viewer
