Calculation From Combo box (1 Viewer)

[PicassoB]

Hi could any one help with a problem I am having getting a calculation to work from a combo box - The product and cost come from a drop down list, cost comes from colum 2 - calculation works fine until I do the total sum which comes up blank or error. attached is a jpeg of the form in design and screen veiw
looks straight forward but have been trying different things for hours with no success :banghead:

 

[MStef]

Try this:
In the CONTROL SOURCE poropeties (in Total field) put:
=Sum([Name of the field])

I think "Name of the field" is "Total product cost",
without a sign ".

 

[PicassoB]

Hi MStrf, thanks for the responce I have allready tried this, still comes up Zero must be some thing so simple i cant see it