Su internet ho trovato questo, purtroppo è in inglese ma non credo sia un problema no? :look:
Create a new user account and check.
a) In the new Metro interface, you can find the Control panel App.
b) Click on the Control panel. When you click on the control panel, main screen of control panel will be displayed
c) Find an option which is named as "Users."
d) Click on the Users, you will taken to a user screen, where you will see four options “change your password, create a picture password, create a pin and the forth one is other users".
e) Below the other users, you will find a button with "+" symbol. Click on it, you will taken to the next screen.
f) In this screen, you can create a separate user account. If you has a Windows Live id. You can use it to create an account.
g) If you don't have a Windows Live Id, you can click on the "More login options". You can select a local account.
h) Fill the details in the local account, and click on Next.
i) A new user account will be created. Now, you can login with the new user account.