Can't Delete File

I'm using Windows Vista.

I have this MPEG-4 (.mp4) file that just wont let itself be deleted. It asks for permission ( i am the admin ), and when I hit the continue button, which has the admin power picture on it, it says I need permission to delete.

How do I delete this file???

I thought I had admin power to do so but it doesn't work.

Hello,

Download unlocker from here:

http://www.filehippo.com/download_unlocker/

Use it to delete the file.