After you’ve logged into your computer, press “Ctrl, alt, del” on the keyboard.

It will come up with a list of options, one of them is “Change Password”

 

It will open your default Internet browser and take you to your account profile.
If prompted login again using your current details.
Click on the “Change your password”

Enter your old password and your new password and click submit.
Restart your computer and try to login with your new password.