Most likely thing is your 'puter doesn't know what program to use to play them, or you don't have a "source" set for the midi sounds.

If you're using the default Windows player, look in Control Panel (Start-Settings-Control Panel) and double click on the "Sounds and Audio Devices," or whatever's the nearest equivalent in your version. There should be an "Audio" tab, that will bring up a box for "midi."

Just make sure there's something in the box. It may give you several choices, so just try them until one works, unless you know what midi stuff you've got.

If that doesn't work, midi may have gotten "associated" with some other program. Click on "Tools" in Windows Explorer, "Folder Options," and the "File Types" tab. If midi (.mid) files are being sent to a specific program that looks wrong, you can change it there; or, once you've identified a midi-play program, you may prefer to go to that program and make sure you have a "sounds" source turned on.

John