\\hostname\admin$

When I go to Start–>Run–>cmd and type in \\hostname\admin$ I am not able to put in the Administrator name and password. All that I can do is put in a “Guest” password. In the connect to \\hostname dialog box it comes up as Username: hostname\Guest and is grayed out. I am able to put in a password. I have disabled the guest account so I am confused as to why this would come up.

Thanks