Quote Originally Posted by cross
When I ran into this issue, I ended up having to set a password for my user, a blank pass wasn't working for some reason.... Stumped me for a bit!
I don't know if this is relevant, but I had a similar problem accessing a PC via Remote Desktop. The PC was in a lab and the Administrator account didn't have a password (yes, I know this is bad practice in a "real live" situation!). When I tried to connect to Administrator and no password, it generated an error. I googled then went to:

Local Security Settings > Local Policies > Security Options then changed the third one listed - "Accounts: Limit local account use of blank passwords to console logon only".