I do not know anything about ophcrack, however, we use a program called Active@ Password Changer. It’s a commercial program that is very inexpensive and it works with all Windows OS that I have tested with. Just create a boot CD or Floppy, boot up and select your account and reset the password. This will strip the password from the account. Only gotcha to be had is if you have encrypted data of any kind, I think you will lose the ability to access that data because the encryption is tied to the password.