SQL 2008 SELECT

Hello,
Can you please help,
I'm trying to do a simple select.

SELECT * FROM ScanItem where scanin is Null   (I get proper results - all data )
SELECT * FROM ScanItem where scanin is Null  and CCDriverNumber is NULL (I get proper results)

When I add another AND, I get no results. (i SHOULD GET FEW HUNDERED)
SELECT * FROM ScanItem where scanin is Null  and CCDriverNumber is NULL AND CCDriverNumber <> 2529

What am I missing?

thanks