Unable to log onto windows xp

[Duo]

I've had my computer for a few months now and I am the
only user so there is only one windows account. As such,
I've set it so that Windows always comes right up with no
need to go to a logon screen. However, a few days ago
when I turned on my computer, the logon screen came up for
some reason. I had no password set, so I just hit enter.
But instead of letting me in, I got a message that
said "THE LOCAL POLICY OF THIS SYSTEM DOES NOT PERMIT YOU
TO LOGON INTERACTIVELY." Please, If someone could help me
it would be greatly appreciated. I have been locked out
of my own computer for three days and I dont know what to
do.

 

[Michael Solomon \(MS-MVP Windows Shell/User\)]

XP Pro or Home Edition? If Pro, is this computer used to log on to a
Domain?