Windows Xp reads information from media to let you find out properties (width, height, bitrate and/or others) of avi, mpg, asf, etc. files. This “behavior” can lock your avi files from being deleted, moved or renamed, and sometimes it’s just plain annoying.
To disable this action, use Regedit to delete the “Default” value for the HKEY_CLASSES_ROOT\SystemFileAssociations\.<EXT>\shellex\PropertyHandler key (where <EXT> is the extension you want to disable for. example: HKEY_CLASSES_ROOT\SystemFileAssociations\.avi\shellex\PropertyHandler).
You can unregister the media indexer for all media files by running
regsvr32 /u shmedia.dll
and/or unregister the image indexer with
regsvr32 /u shimgvw.dll