Method 1: Revert to System Restore point
If this has just starting happening to you in the last couple of days, the easiest way to get things back to normal is just to restore your computer to a point before the problem starting occurring. The issue here is that there are some files that may have become corrupted in Windows Media Player and therefore do not load AVI videos properly.
Method 2: Install/Re-install Codec Packs
The other issue could be with the particular codec pack you are using. By default, Windows Media Player should be able to play AVI files without any codec pack. However, sometimes installing a third-party codec pack will fix the issue. My favorite codec pack that works very well is K-Lite Codec Pack. It’s got all the latest codecs and doesn’t conflict with other software on your system. You may also want to try installing ffdshow.
Method 3: Convert AVI video to WMV video
Windows Media Player supports WMV video better than AVI video, you can use this Total Video Converter to convert your AVI video to WMV video for a try, here is the video converter directly download link, it’s about 7.2 Mb, I have scanned it with AVG and Norton, it’s safe without any viruses and spyware. Then install and run the video converter, drag the AVI video into the software, select “WMV” as output profile, click Start the run the process, and then you will get a WMV video which is compatible with windows media player.
Method 4: Check Windows Media Player File Association
The next thing you can try is pretty obvious, but may solve your problem. Open Windows Media player and go to Tools and then Options.
Now click on the File Types tab and make sure that AVI is selected in the list. If it’s not selected, it may be the reason why your videos are not playing.
Method 5: Reinstall Windows Media Player
If none of the above solutions worked, you may want to try and reinstall or upgrade Windows Media player to see if that fixes the problem. However, in my case, upgrading from Windows Media Player 10 to 11 didn’t help!