Security – There are currently no logon servers available

I am running a Windows 7 laptop that is joined to my company's domain. When I installed Windows 7, I created an account for myself, joined to the domain, and it had been working quite well even though I'm physically remote most of the time, and not actually on the network.

However, today I created a new local user account (non-admin) for my little brother. While he was using it, he decided he wanted to install a program, because his account is not an admin, he was prompted to enter Administrator credentials to allow the program to make changes to his computer. I entered my credentials, and this is the first time I ran into the error message:

There are currently no logon servers
available to service the logon
request.

I tried logging off and loggin back in, rebooting, etc etc, and no matter what, every time I try to authenticate as my "normal" domain account – I get that message.

I can no longer access my computer as an administrator. I no longer know how to log in to my machine using any other account aside from my little brother's non-admin account.

I don't have any other local accounts created, and the default local admin account was never enabled.

I'd appreciate any ideas on how I can recover access to my account. Let me know if I can provide any more information.

FYI – This is a similar question but not sure any of the answers help me in my case. Error "There are currently no logon servers available to service the logon request"