This article describes the Guest account.

The Guest account in Windows XP Home Edition and Windows XP Professional (when not joined on a domain) serves several special functions that relate to security and network shares. Because of its importance, you must not disable the Guest account. If you disable the Guest account, your network can have problems that include malfunctioned shares.

In Control Panel, you can use the User Accounts tool to turn off the Guest account, which removes the listing of the Guest account from the Fast User Switching Welcome screen; however, the Guest account is not disabled.