Calculating duration of on/off

I'm sure this has been answered out there, I just can't seem to find the right search condition

DECLARE 
@OrderRanking   as table
(   Orderdate datetime NOT NULL
,   Duration int
,   durstatus int   )   
INSERT @OrderRanking (Orderdate, Duration, durstatus)
SELECT '2014-03-10 10:55:12.000', 1000, 1
UNION SELECT '2014-03-11 10:55:12.000', 500, 1
UNION SELECT '2014-03-14 10:55:12.000', 650, 1
UNION SELECT '2014-03-15 10:55:12.000', 3000, 0
UNION SELECT '2014-03-17 10:55:12.000', 1000, 1
UNION SELECT '2014-03-17 11:55:12.000', 2000, 1
UNION SELECT '2014-03-18 10:55:12.000', 500, 1
UNION SELECT '2014-03-20 10:55:12.000', 500, 0
UNION SELECT '2014-03-21 10:55:12.000', 500, 0

select * FROM @orderranking

--what I'm going for
SELECT '2014-03-10 10:55:12.000', 2150, 1
UNION SELECT '2014-03-15 10:55:12.000', 3000, 0
UNION SELECT '2014-03-17 10:55:12.000', 3500, 1
UNION SELECT '2014-03-20 10:55:12.000', 1000, 0

Essentially I need to sum up the duration each time the dur status flag switches, easy to do with a cursor, but I'm sure there's a CTE/ranking type solution out there. I'm on SQL2005 at the moment.

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Best Wishes, The Redman; If something helps, please help show it by voting, if it solves, bonus!