Guest Accounts in Windows XP
When several people use a single computer, it’s convenient to set up a user account for each person to keep everyone’s setup preferences and documents separate. If someone wants to use your computer briefly he or she can use the Guest user account. By default in Microsoft Window XP, this account is disabled, which means that only specifically authorized users can access your computer.
If you have enabled your Guest account, you should disable the Guest account (once your guest has finished using your computer) to improve your computer’s security.