1. Convert the file into a video file. Double-click on Windows Movie Maker. From within Windows Movie Maker, move the mouse to the upper left-hand corner and left-click on "File," then left-click on "Open Project" in the drop-down menu. Select your MSWMM file from the new window and double-click it. This will open the project in Windows Movie Maker. From here, click on the "Movie Tasks" tab on the left side of the screen and scroll down until you find the option to "Save to My Computer." Left-click on this option and save the movie file to your computer. It will be saved as a WMV video file, which is what you need to create an AVI file.

2. Configure online settings for the Media-Convert.org website. Go to the Media-Convert website listed below in the "References" section. In the center of the screen, you will see a "Browse" button, and an "Input Format" drop-down menu. Click on the "Browse" button, find your WMV file and double-click on it to insert it. Next, click on the drop-down menu and select "Windows Media Video (.wmv)." Below the menu, find the two "Output Format" drop-down menus. In the first drop-down menu (left to right), select "WINDOWS DivX." In the second drop-down menu, select "Audio Video Interleave (.avi)."

3. Finish creating your new AVI file. If desired, type in your email address under the "Advanced Settings" section of the website. This will send a notification email when the file is done converting. Finally, click on the "OK" button in the lower right area of the website. A small loading icon will appear below it. Be prepared to wait, as this may take hours to finish. Upon completion, a new download button will appear. Click on this and your newly converted AVI file will be downloaded on your computer.

basicaly you type in google or cnet mswmm to avi convertor download is then attach the file then finished 

good luck :)