>>Could you post it in XML format?
>
>I have attached it.

According to the execution plan, SQL engine runs 2 separate queries and than merges them. I would bet that the execution plan for a JOIN query would be the same or close. IOW, I don't thibnk that switching to exists changed anything.

SELECT Member.Numero,Member.Nom,Member.Prenom,Member.LastAccess
 FROM Member
 WHERE Member.LastAccess>=@LastAccess AND
-- And 
SELECT Monitor.NoMember2 FROM Monitor WHERE Monitor.NoMember=@NoMember

I don''t see anything wrong with query itself. Are there any other SQL statement in your system that uses those 2 tables and could cause the deadlock?