If you need to let someone log on to your computer but you don't want them to have access to all of your files, you can create a guest account. Because the guest account allows a user to log on to a network, browse the Internet, and shut down the computer, you should disable the guest account when it isn't being used.
These steps cannot be completed on Windows Vista Starter, Windows Vista Home Basic, and Windows Vista Home Premium.
The steps that you should follow will vary, depending on whether your computer is on a domain or a workgroup. To find out, see "To check if your computer is on a workgroup or domain" in How is a network at home different from one at work?
Click Manage user accounts.
If you are prompted for an administrator password or confirmation, type the password or provide confirmation.
Click the Advanced tab, click Advanced, and then click Users.
In the Guest Properties dialog box, select or clear the Account is disabled check box.
Click Users, and then double-click Guest.
Select or clear the Account is disabled check check box.