First figure out why you're getting the error. You could be getting it
because it's in use or you could be getting it because you don't have
permission to delete it. If it's the first option you have to find the
program that's using it and shut it down to then delete the file. If it's
the second option you have to be administrator to delete the file, if you're
already administrator then either change the permissions or take ownership
of the file then change permissions to delete the file. If these don't work
then you've got something going on that requires some investigation.
Joe