Highlighting reaccuring info in a spreadsheet

[wmead]

How would I be able to highlight information in a spreadsheet that is
repeated through out the spreadsheet?
e.g.

acc# name due date start date
111 tm 1/12 1/10 <---------
222 np 11/08 10/08
333 cm 1/13 2/3
111 tm 3/4 2/5 <---------
444 sm 1/2 9/2

How would I highlight or format or mark in some way the two lines I have
arrows on. Notice that the dates are different but the other stuff is the
same. This is a simple example I have over 700 rows I have to go through and
there is over 20 columns of info for each row. I know over a hundred of these
rows repeat and I need to highlight them in some way. Any help would be
greatly apreciated.

P.S.
Sorting and then highlighting by clicking on the reacurring items is not an
option.

 

[Fred Smith]

The general way to do this is to count the duplicate occurrences. Use a
formula like:
=SUMPRODUCT(--($A$1:$A$1000=A1),--($B$1:$B$1000=B1))
and copy it down.

Now filter all the results greater than zero. Or set a conditional format
based on value > 0.

Regards,
Fred

 

[wmead]

I knew there was a formula I could use. Thank you so very much.