Cannot delete file, being used by another person or program

[threeonefour]

"Cannot delete file because it's being used by another person or program."

i got this error message while trying to delete a file recently. The file was MSNmessenger's install exe that i was just downloading but was corrupted when i canceled the download early on accident.

http://www.computerhope.com/issues/ch000714.htm

the link above will take you to a description of the problem as well as a solution. My problem is that i have tried all those methods (restarting the computer then deleting, restarting in safe mode then deleting) and i still get the exact same error message.

does anyone know how to force delete something like this?
thanks