copy formula down entire column while changing formula cell reference

Hi there I would like to copy the following formula down the entire column.

Please Login or Register  to view this content.

When I do the classic drag down it changes F2 to F3,F4, and so on while keeping the C4 and D4 as is. This however is not what I require!
I would like the formula, as you go down the column, to look like this:

Please Login or Register  to view this content.

What I am thinking is to somehow achieve the following, could someone help me translate this to VBA, or perhaps suggest a better way of accomplishing this:

Please Login or Register  to view this content.

wow, miss the obvious again...aparently i enjoy overcomplicating things. thanks a lot, that was headsmack i needed. much appreciated.