How to delete a .mov file??

I have a quick time video i got from web and whenever i try to delete it or rename it , it gives me an error: cant delete , it is used by some other person or program!.
Although i can play the video.
i have tried to reboot and delete it but still the problem persists.

i have tried editing this key: HKEY_CLASSES_ROOT\SystemFileAssociations\.avi\shellex\PropertyHandler

Click to expand...

as well as deleting the file through command prompt.
i m using windows xp sp2.
it wud be great if ne one has solution for this annoying problem?