You can't open it directly while Windows is operating. Even if you could all you'd see is a long hash string encryption. The passwords are encrypted so no text of the passwords even exists.
If you still want the hash strings, use a Live Linux boot CD to extract the file. It's still just gibberish but at least you'd have the encrypted hash. You could then use a decryption program.
By the way, if this is for Windows 7, why did you create the thread in the Windows XP section?