I need a macro that can enter a serial number in a given row in column A
based upon whether or not there is an entry in the same row in column B.
There are often a number of blank spaces between the entries in column B.

To make matters worse, the number needs to increase by one with each
occurrence.

Is there a macro like this floating around anywhere?

Any help greatly appreciated. I'm a newbie, and am faced with the prospect
of sorting through 60,000 rows, one entry at a time. My boss is growing
impatient :-(

jdh