windows xp workgroup password problem

I HAVE A PROBLEM WITH WIN XP PROFESSIONAL.I WAS LOGGING IN WITH ADMINISTRATORS PASSWORD BUT NOT GETTING ACCESS TO NETWORK RESOURCES. I DID A RIGHT CLICK ON MY COMPUTER AND CHANGE THE DOMAIN TO THE WORKGROUP.The system asked me for user account with prmission to log on and i typed Administrator.It also asked for my administrator password.It accepted my password and welcomed me to the workgroup.It also asked for a restart of which i did.When it prompted me i typed in the Administrator and the password.Them machine is not accepting my administrators password.I CANT GET IN.What might be the problem.I AM STUCK’its not accepting a blank password as well.