I'm trying to use conditional formatting to compare two columns of figures.

I have two columns and wish to highlight in red where the cells in column B
don't match the cells in the equivalent row in column A.

I can set up conditional formatting for one cell but I don't know how to
copy this to other cells in the column. I thought I'd managed it but it kept
using absolute referencing back to the original cell, rather than the cell in
the corresponding row.

I really don't want to have to set up the conditional formatting for each
row. I've done it before but can't remember how. I'm using Excel 2007.

Help appreciated. Thank you.