Logon problem in XP

I have a Dell XPS desktop running Windows XP (SP2).
Today tried to download windows Easy Transfer at the Microsoft site and MS first verified my copy of XP (OK). Download of Easy transfer failed due software not being currently available-please try again. Computer then locked so I used winndows restart and

When windows screen loads I am asked for my password- I don't have one so I hit enter and then get message"Unable to log you on because of an account restriction."

Restarting computer I can go to boot set up ans see that neither system or administrator has a password installedd.

Restart computer and try quick taps on F8 button duting Dell screen to access safe mode but always get windows screen and password request .

Can any expert help please?
Thanks