Like all media files, Windows Media Videos (WMV) can become broken or corrupted. This could be caused by a virus, a mistyped file name or a bug contained in the video files itself. Several programs exist to fix corrupt WMV files. Running any one of these should clear your WMV of any bugs or viruses and get it playing in Windows Media Player or any other WMV-compatible application.
Repair the corrupt WMV file with Steeper (link in Resources). This free program presents a very basic interface, but is powerful enough to repair many WMVs. "Open file" lets you load the corrupt WMV and "Repair file" fixes it. It's simple and elegant and doesn't cost a thing.
Repair the corrupt WMV file with ASF-AVI-RM-WMV Repair (link in Resources). This tool will fix all the video formats listed in the title. After installation, you simply click the large "Add file" button to select your corrupt WMV. A "Repair" button analyzes and repairs the file. The program costs $34.95 (as of October 2010), but the company offers a fully functional 10-day free trial.
Repair the corrupt WMV file with All Video Fixer (link in Resources). This program offers quite a few options, but presents a basic navigation system. The trick here is that the program saves a new, fixed version of the WMV. The "Add media file" button lets you load the corrupt WMV. There is a preferences folder where you can select the output folder for the fixed WMV. Then the giant "Play" button does the rest, showing you a progress bar as it runs. The program costs $34.95 (as of October 2010).
If you got the WMV file online, be sure the download completed successfully. If it didn't, no repair program can invent the missing data.