Conditional Formating - by row, not by column (Office 2007)

[bp]

Hi. I have a spreadsheet with 100 rows of data. There are drop downs in
columns M-P. I want to do conditional formatting by row (not column) to
highlight when cells M, N, O or P have duplicate values. I've been able to
get this to work by highlighting a row of those 4 cells one at a time, hiting
conditional formating -> highlight duplicate values but I don't want to have
to do this for every row like this. I haven't been able to figure out how to
copy this down so the conditional formatting looks across only and not down
for repeat values. Help would be appreciate. Thanks!

 

[JE McGimpsey]

One way:

Select M. Assuming M1 is active:

CF1: Formula is =COUNTIF(OFFSET($M1,,,1,4),M1)>1