Windows XP help - Password

-----Original Message-----
Hello,we have tried networking this pc with our other pc
which is brand new....It has our registered copy of
windows xp on it.For some reason,the other pc has
started
prompting for a user name and pass-word at the log-on
screen.We have never created a pasword,there-fore we
cannot get windows started.Please help as this is so
frustrating.I have tried the recovery console but that
is
asking for an administrator password aswell!!We've come
to a dead-end...Thank-you
.