How to change Windows password
Your Windows password is the password you use to log on to your computer. You can help keep your computer more secure by changing your Windows password regularly and by using a strong password. For more information about strong passwords, see Tips for creating strong passwords and passphrases.
Press Ctrl+Alt+Delete, and then click Change a password.
Type your old password, type your new password, type your new password again to confirm it, and then press Enter.
If you have forgotten your password and you have a password reset disk, you can reset your password. For more information see, Reset your Windows password.