The issue seems to be one where if this is a legitimate need to unlock or reset the password, you might wish to contact Microsoft's support team and provide them valid information on how to help you. Otherwise, your only options would be attempt to make a backup of data using an external drive, running the system image restore to factory settings and then moving your data to the restored drive.
Outside of this, there isn't a way for the forums here to provide you with information on how to hack an admin account, regardless if it is your own. This kind of post could apply to any PC that is 'acquired' either legally, or illegally.
There is a reason password and encryption exists- it is to prevent someone from gaining access to an account in which they do not know the login information. If you do not now the account login or password, or a legitimate administrator account to login with and change the other- you are likely not going to be able to access the PC. If you are going to search for ways to do this, please do so via search engine and by not asking these kinds of questions on these forums- it is against forum rules to solicit ways to bypass system security features.
Closing thread.