To set up a Macintosh so it will play Midi files, you will need Netscape 2.0 or later, a midi plug-in and Quicktime and Quicktime Musical Instruments 2.0 or later.

Put the plugin in the navigator's "plugin folder" then follow Arnold's instructions for enabling it and properly setting mime type. If using Quicktime 2.5, use the "QT settings" control panel to select QT midi or an external midi device.

My own setup is:
PowerMacintosh 7500/100, 32MB RAM, L2 cache
PowerBook 520, 20MB RAM
MacOS System 7.5.5
Quicktime 2.5
Netscape 3
Arnaud Masson's MidipluginPPC (also available as Midiplugin68K)
OMS 2.2 (Opcode's Open Music System)
Nightingale (MusicWare) and Overture (Opcode) to make midi files.
Virtual memory on (VM off in prior MacOS)

Quicktime and other system software updates can be found at Apple Support and Information.

Arnold's Midi Player Home Page is the source of an excellent midi file player and includes good links to midi information. See also "Interesting Links" on my home page.

For Windows machines: Try MidiGate at http://www.prs.net/midigate.html, a midi plugin for Windows. This site gives instructions on how to set up the computer using a sound card. Quicktime for Windows is available at Apple Support and Information.

Go to Composer's Tools or use the "back" button of your navigator.