So if your description is accurate, it sound like a blocking issue. When you create a linked server, you are only updating the local system catalog. You are not connecting to the remote server. That will not happen until you use the linked server in a query or try the Test Conncection button.
Why it would be blocked? Well, maybe someone did
BEGIN TRANSACTION
EXEC sp_addlinkedserver YOURSERVERNAME
And left that transaction open.
You could use sp_who2 while SSMS is open to check for blocking.