I need to compare cells to the cell above them and to the right of
them.  Based on the comparisons I'll need to update the original cell
with one of those adjoining cell values.  After I finish with one
column then I need to repeat the procedure on the column to the LEFT
of the original column.

I know IF, THEN and ELSE statesments but I don't know VB for Microsoft
Office products.

Range could be all 65,000+ rows on a workseet

Start on ColumnJ, Row2

If ColumnJ, Row2 is Null _
  If ColumnK, Row 2 is Not Null _
     If ColumnJ, Row 1 is Not Null _
        ColumnJ, Row2 Value is updated to match ColumnJ, Row1
     End If
  End If
End If

Loop Back and compare the next Row on the original column.
When all Rows are checked then start over at ColumnI, Row2

Even a macro doing this one column at a time would be incredibly
helpful.

Thanks!

Nick