Just look in your services on your CLIENTS. The only service related to SQL (if there is one there) would be SQL Server VSS Writer, which is no longer needed after 2003 OS. However, it came with XP and as I just checked, it comes with Vista and WIN7 as well.
You can also download Studio Manager for Express, but it will do little good without the sa password.
http://www.microsoft.com/downloadS/...E3D-94B8-5A0F62BF7796&displaylang=en
