Windows 8.1 - How to change your password (Microsoft account)
When you first install Windows 8.1, you need to link it to an e-mail address and implicitly created a Microsoft account. By default your password, will be the one used for your Microsoft account. How to change it?
Press Windows + X > Control Panel.
Click on Accounts and Family Safety.
Click on User Accounts.
Choose Make change to my account in PC settings.
From the Start screen. press Windows + C to display the Charm Bar.
Click on Settings > Change PC settings > Accounts
Go to the Sign-in options and under A strong password makes your PC more secure, click on Change.
A new menu will be displayed:
Enter your current password and then your new password.