Login as user "Administrator" vs. ".\Administrator"

Question

I'm using Remote Desktop to log in to a remote machine.

What is the difference between specifying .\ before the username, and not?

For example:

Username = Administrator

and

Username = .\Administrator

Answer 1

In example A you would be referring to the Domain Administrator (if you had one).

In example B you would be referring to the local Administrator account on the specific PC.