karrde said:
  1. Start the Windows Registry Editor program:
    Start -> Run -> regedit
  2. Navigate to the following key:
    "HKEY_CLASSES_ROOT\.xyz\ShellEx\{BB2E617C-0920-11d1-9A0B-00C04FC2D6C1}"
    (replace .xyz with the desired file extension like .avi or .mkv)
  3. Right-click on "{BB2E617C-0920-11d1-9A0B-00C04FC2D6C1}" and select Delete.

Or alternatively if the DivX preview cause the explorer hang/crash: unregister and/or rename "DivXThumbnailProvider.dll" (at C:\Program Files\DivX\DivX Plus Media Foundation Components\ ).

right on we'll see