Windows 8 - Change the administrator password
When you first buy/installed your Windows 8, 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?
Via the Control Panel:
Press Windows + X > Control Panel.
Click on "Accounts and Family Safety"
Click on "User Accounts"
Choose "Make change to my account in PC settings"
Via the Charm Bar
From the Home-screen. press Windows + C to display the Charm Bar.
Click on Settings > Change PC settings > Users Tab
In the "Sign-in options" section, click on "Change your Password".
Changing your Password:
A new menu will be displayed:
Enter your current password and then your new password.
Confirm and click on Next.