Occasionally you won't be able to delete or even move an AVI file, because as soon as you click on the file, Explorer hangs while trying to offer a preview of it. This usually happens when the AVI file is incomplete or corrupt. A quick Registry fix will unlock your AVI's so you can move or delete them. Simply follow these steps:
1. Click on the Start button and select 'Run'
2. Type in 'regedit' and press 'OK'
3. Look for the following key:
HKEY_CLASSES_ROOT\SystemFileAssociations\.avi\shellex\PropertyHandler
4. In the right pane right-click on 'Default'
5. Select 'Delete' then 'Yes'
6. Exit the Registry and reboot your computer
