...make sure you're in as admin...then shut down all but essential processes on the machine with Task Manager...then give a shot at del ..filename.. and see it that works.
Maybe this baby has attached itself to a process that you can kill.
drill down to one level above the file and use deltree.
"When it crosses my mind to do something, I don't ask why, I ask why not. And usually there's no reason not to, so I just go ahead. It's given me the strangest collection of hats"