How to set Administrator Password in Windows without knowing Existing Password

1. Go to Control Panel.

2. Click on Administrative Tools.

3. Click Computer Management.

4. Go to System Tools.

5. Double click on Local Users and Groups.

6. Under users, you will see all user accounts including admin account.

7. Right click on administrator and click set password.

8. It will not ask for previous password so you don't need to know it.

9. All done.