With XP using IIS5.x, use the Application Protection option on the 'Home Directory' or 'Directory' tab in the website properties pages. If you configure for "Low (IIS Process)", the SYSTEM account is used, and you will need to give the SYSTEM account database access (assuming the DB is on the same machine).
Jim Cantwell
InfoPathDev Redmond
Jim Cantwell
InfoPathDev - Redmond