Excel 2007 : How do I show a dragged formula as zero?

[fithawk]

I have a table to monitor my holidays that contains auto formulas to count. The problem I have is when dragging my formulas down a column excel inserts the last value all the way down the page. How do I format to stop this? Sheet attached.

[zbor]

Is data in A column mandatory?

In thtat case you can use it as reference in all other cells:

=IF(A2="", "", your formula)

Or only in E column:

=IF(A2="", "", C2*D2)