I had the same problem with the log-on screen. So I moved the *.pwl files to another folder (rather than deleting them), restarted, clicked 'OK' when prompted for a password, rebooted and yeah! no more password requests.
Now, however, Network Neighborhood only shows me the 'Entire Network' icon and produces the 'cannot browse' error when double clicked. I didn't change any network settings when I got rid of the *.pwl files. I moved those files back into the Windows directory - still no password requet, still no computers listed in Neighborhood -
Co-incidence or cause and effect?? The network adapter shows a strong connection to the network.