Windows Media Player plays AVI files by default, so double-clicking on the file should allow it to run in the player. If it does not work, you may have to enable AVI playback in the menu, and check for updates to ensure it plays supported files in the future.
- Update to the newest player
Open the Control Panel, and type "Windows Update" in the search field. Click on Windows Update, and run the scan. Update the player to the newest version, as an older version may be causing the problem. For older computers that cannot run the newest version, you can find an option to enable AVI in the menu.
- Enable the Tools menu
Windows Media Player 12 offers full support for AVI; however, if you cannot update to the newest version, press the shortcut keys "Ctrl+M" to show the menu. Click Tools, and select Options.
- Check for AVI playback
Click the Files Type tab in the new pop-up window. Make sure you see a check next to Windows video file (avi) in the list. If not, check the tick box to enable playback. Afterward, open a Windows Explorer folder, and find an AVI file. Double-click to play the video in Windows Media Player.