Log in as a computer Administrator... or Domain Administrator if you are on a big network.
Open explorer, go to the directory before the locked folder or file, and right click - properties.
Pick the security tab.
It may give an error saying that you don't have access to change rights... that's ok, contiune on.
In the advanced section (forgive me, this is from memory)...
One of the tabs says Ownership. Do a take ownership. Go back to permissions page and you can now modify rights. You may have to totally remove the existing permissions first before it will let you do anything.
Once you are the administrator and the folder owner you can do anything you want, even if the permissions say otherwise.
-Teva24
Take heed, adivce from the sleepy might uhh... you know.