That's done a long time ago with a little tweak in the registry (regedit). WMP play well with the synth but not NoteWorthy Player. Maybe the program is too old. I hope that the Noteworthy Viewer 2 will support Midi files
I try to listen to my midi in NWP 1.75 (32 bits version) and By default it load Microsoft Midi Mapper. I want to use SB X-Fi Synth A with Soundfont. In Vista 64 bits all my setting is correct. Even In composer I can choose my synth. The problem with NW Viewer it can't read midi file (.mid,.rmi, etc.)