creating a windows athentication login

Hi all. Here is my problem. Computer A has sql server 2005 express installed on it together with sql management studio. Computer B has only sql management studio. Computers are members of a corporate domain and are running xp professional. After starting management studio on computer B the databese engin on computer A is visible in the 'select server to connect to' dialog under network servers. When i try to connect i get the message login failed - so i try to add a windows athentication login for the appropriate user on computer A. The problem is as follows: Under 'Create new login/Select user or group/location' no network location apear and i can not add a network user name. This seem to be a network connectivity issue. I have, however, adjusted network connectivity via surface area configuration and enabled tcp/ip and named pipes - the server is visible form another computer as i have prviously mentioned.

I am not sure how you go there in the GUI. Do you right-click the Security->Logins folder and choose New Login?

From T-SQL, you can just use

CREATE LOGIN domain\user FROM WINDOWS