SELECT TOP (100) PERCENT
        dbo.v_R_System.Name0,
        dbo.v_GS_ADD_REMOVE_PROGRAMS.DisplayName0,
        dbo.v_GS_ADD_REMOVE_PROGRAMS.InstallDate0,
        DATEDIFF(Day, CONVERT(date,dbo.v_GS_ADD_REMOVE_PROGRAMS.InstallDate0), GETDATE()) AS [days since installed]

FROM
        dbo.v_R_System INNER JOIN
        dbo.v_GS_ADD_REMOVE_PROGRAMS ON
        dbo.v_R_System.ResourceID = dbo.v_GS_ADD_REMOVE_PROGRAMS.ResourceID
        
WHERE
        (SELECT ISDATE(dbo.v_GS_ADD_REMOVE_PROGRAMS.InstallDate0)) = 1

GROUP BY 
        dbo.v_R_System.Name0,
        dbo.v_GS_ADD_REMOVE_PROGRAMS.DisplayName0,
        dbo.v_GS_ADD_REMOVE_PROGRAMS.InstallDate0,
        DATEDIFF(Day, CONVERT(date,dbo.v_GS_ADD_REMOVE_PROGRAMS.InstallDate0), GETDATE())

HAVING
        (
        (CASE WHEN (ISDATE(dbo.v_GS_ADD_REMOVE_PROGRAMS.InstallDate0))=1 THEN
                (DATEDIFF(Day, CONVERT(date,dbo.v_GS_ADD_REMOVE_PROGRAMS.InstallDate0), GETDATE()))
        ELSE    500
        END) > 0 AND 
        (CASE WHEN (ISDATE(dbo.v_GS_ADD_REMOVE_PROGRAMS.InstallDate0))=1 THEN
                (DATEDIFF(Day, CONVERT(date,dbo.v_GS_ADD_REMOVE_PROGRAMS.InstallDate0), GETDATE()))
        ELSE    500
        END) < 7
        )