Logon failure account currently disabled

I am confronted with this same problem in my home network:

I have two Windows 7 laptops, 1 XP desktop and 1 Windows 7 deskop. All systems are set up to work without password. I can access my WD MybookLive Duo with the first 3 machines, but not with te Windows 7 desktop. I checked all security and firewall settings between the ‘good’ Windows 7 systems and the ‘bad’ Windows 7 system to make sure they are all equal. Still the problem is not solved. I cannot access my NAS from this desktop because of  ‘account currently disabled’.

Is this a NAS settings problem or a Windows settings problem?

Please provide some more suggestions to get this working.