This can occur if you manage to delete all local user accounts (User
Accounts won't let you do this, but other account- management tools aren't
as protective) or, in some cases, if you upgrade your computer from an
earlier version of Windows.
If you're using Windows XP Professional, press Ctrl+Alt+Delete two times to
display the Log On To Windows dialog box.
Type Administrator in the User Name box, and enter the password you created
for the Administrator account during setup.
Logged on as Administrator, you can run User Accounts and create one or more
new accounts, which will thereafter show up on the Welcome screen.
Windows XP Home Edition users can't log on using the Administrator account,
which is prevented by account restrictions from logging on.
Instead, you must start Windows XP in Safe Mode by pressing F8 at the
beginning of the startup process. After you're up and running in Safe Mode,
you can run User Accounts to create one or more new accounts.
You may also be interested in this article after creating new accounts
http://support.microsoft.com/default.aspx?scid=KB;EN-US;Q308421&
HOW TO: Take Ownership of a File or Folder in Windows XP
NOTE: You must be logged on to the computer using an account that has
administrative privileges. If you are running Windows XP Home Edition, in
order to have access to the Security tab, you must first start in Safe Mode
and log on with an account that has Administrative rights.
