Download and install AVS Video Converter, free of charge. Agree to the licensing terms and open the program.

Click the "Browse..." button next to the input file name box to enter a pop-up menu and locate the AVI on your computer. Open it in AVS.

Click the "To MPEG" or "To MP4" button at the top of the AVS interface.

Click the output file name "Browse..." button to name your new file and choose its output destination (the location on your computer where AVS will save the file to).

Click "Convert Now!" to begin converting your AVI to MPEG format.

Visit Apple's website and download QuickTime Player (free) and the Pro component ($29.99). Agree to the terms of use, install the program, and open it.

Click "File" and select "Open Files..." to find your AVI in the pop-up window and open it in QuickTime Player.

Select "Export..." from the "File" menu to enter the export options screen. Choose "Movie to MPEG-4" from the drop-down list of export options.

Rename your file, if needed, and choose its output destination. Click "Save" to begin the conversion.

Launch your web browser and navigate to Zamzar.com.

Click the "Browse..." button in the Step 1 box to direct Zamzar to the AVI on your computer. (This will allow Zamzar access to your hard drive).

Choose "MPG" or "MP4" from the drop down list of output format options in the Step 2 box.

Enter your email address in the Step 3 box so Zamzar can alert you when your conversion is complete.

Click "Convert" to agree to the terms of use and begin the conversion. You will receive an email with a download link where you can retrieve your new MPEG when Zamzar is finished.