try the "unlock" command from the prompt. Also, many 3rd party utilities will take "ownership" of a drive if they are configured to run maintenance proceedures in the backgroung.
I like Blue's Port Scanner. It's quick and doesn't consume too many resources. Also, you might look into getting some penetration testing software. Most of it that i've used will portscan, identify missing service packs, and allow you to see what shares are open. Try Nessus or Languard.