If the PC running Windows 8 in your house needs to have another user account, you need to set up a new user. You already know how to add a user in Windows 7 and here’s how to do it in Windows 8.
You’ll need to have Administrator rights to add a new user. Each new user you add will have a Standard User account type.
Add User via Metro UI
In the metro (modern) interface, hover your mouse in the lower right corner of the screen and click Settings in the Charms bar. Or use the keyboard shortcut Windows Key + C to display it.
Then click Change PC Settings.
The new Windows 8 Control Panel will appear. Select Users under PC Settings on the left and click Add a User under Other Users on the left.
Enter in the new user’s Microsoft Account email address. Or, if you want to make them a local user, click Sign In Without a Microsoft Account. Click Next.
The new user’s Windows Account email is displayed, if you’re setting it up for one of your kids, you might want to enable the Family Safety feature.
Back under User Accounts in the Metro UI, the new user will be displayed under Other Users.
The next time the new user logs in, they need to click the arrow to Switch User.
Then they just need to click on their account icon to log in.