find duplicates in two cells per row

[IanMahael]

Hi,
I hope it's not as difficult as it appears to me: I want to find duplicates in a big sheet:
#. column 1 - column 2
#. Name - date.birth
1. Mr.X - 20.11.1985
2. Mr.Y - 20.05.1983
3. Mr.X - 21.12.1954
4. Mr.X - 20.11.1985

The function should find/mark the ones with the same name and birthday in the same row. In the ex. above that would be 1 and 4. I've tried a lot of stuff and it works very well as long as it is only one cell in one row that you compare - but I need to compare the content of two cells.

Any one has any ideas?
[Excel 2003]

[DonkeyOte]

You could use conditional formatting if that's what you mean ?

Simplest thing, to avoid expensive formula in volatile Conditional Formatting, would be to first add the below to column C:

C2: =$A2&$B2
copied down for all rows

Highlight your data (A2:B2 down selecting A2 first) and apply a FormulaIs based Conditional Format rule:

=AND($C2<>"",COUNTIF($C:$C,$C2)>1)
set format accordingly