>Naomi,
>what I need is to know if a specific SQL Server is linked to another SQL Server, if not link whit sp_addlinkedserver...
>not to start-stop the SQL Server.
>For some stupid reasons they want to unconnect a linked server conection from a Web server and when some SQL stranasctions occurs re-establish the conection to send some info to the local network server, a after thar disconect the linked server again.

--- Just run SELECT * FROM sysservers first
--- to decide what you could use to identify your linked server

IF NOT EXISTS(SELECT 1 FROM sysservers WHERE SomethingThatIdentifyYourLinkedServer)
   BEGIN
      --- add linked server here 
   END 

-- Rest of the query.

(That is tested on 2005, you should check it on 2000)