Help with query -SQL Express and ASP.net

I am having trouble with the below query. This is attached to a SQLDataAdapter which in turn is connected to a grid view.

@.pram5 is a dropdownlist
all other perameters such as @.nw in the big OR statement are check boxes.

My tables look similar to this:

Company TblComodity TblRegion

PK CompanyID PK CommodityID PK RegionID
CompanyName FK CompanyID FK CompanyID
CommodityName North
South, East, etc

What I would am trying to do is have a user slect a commodity which is a distinct value from the comodity table. Then select by tick boxes locations, then in the grid view companies with possible locations and commoditys appear. My problem is even when I select a commodity and leave all tick boxes blank (false) the records still display - like its only filltering on commodity name. Can anyone help ? I can provide more info if needed

Here is my query:

SELECT TblCompany.CompanyID, TblCompany.CompanyName, TblRegion.NorthWest, TblRegion.NorthEast, TblRegion.SouthEast, TblRegion.SouthWest,
TblRegion.Scotland, TblRegion.Wales, TblRegion.Midlands, TblRegion.UKNational, TblRegion.EuropOotherThanUK, TblComodity.ComName
FROM TblCompany INNER JOIN
TblRegion ON TblCompany.CompanyID = TblRegion.CompanyID INNER JOIN
TblComodity ON TblCompany.CompanyID = TblComodity.CompanyID AND TblComodity.ComName = @.pram5
WHERE (TblRegion.NorthWest = @.nw) OR
(TblRegion.NorthEast = @.NE) OR
(TblRegion.SouthEast = @.se) OR
(TblRegion.SouthWest = @.sw) OR
(TblRegion.Scotland = @.scot) OR
(TblRegion.Wales = @.wal) OR
(TblRegion.Midlands = @.mid) OR
(TblRegion.EuropOotherThanUK = @.EU) AND (TblRegion.UKNational = @.UKN)More info needed: Are the ticks mapped to the appropiate parameters like @.sw ? What do you pass if the ticks are not selected ? Probably Null ? because of doing an OR, you will get all values which habe in one of the filtered columns the value null then.

HTH, Jens K. Suessmeyer.

http://www.sqlserver2005.de