Updated February 10, 2017 Right-click on the MP4 file you want to play and select “Open With.” In the dialog box that appears select “Select the program from a list” and click “OK.” Choose “Windows Media Player” from the list of programs that appears and select “Always use the selected program to open this kind of file.” and click “OK.” If Windows Media Player does not show up on this list proceed to step 3. Click “Browse” and go to the directory where the Windows Media Player executable file is located. This file can usually be found by going to the “C” drive, then “Program Files,” then “Windows Media Player.” The file’s name is usually “wmplayer.exe.” Select that file as the program you want associate with MP4 files and click “OK.” Writer Bio
