You could use either Conditional Formatting or Data Validation:

Conditional Formatting:
=COUNTIF(B:B,$B$3)1

Data Validation:
=COUNTIF(B:B,B2)=1
and check ignore blanks

--
HTH

Sandy
In Perth, the ancient capital of Scotland
and the crowning place of kings


Replace @mailinator.com with @tiscali.co.uk


"Dr Alok Modi MD" wrote in message
...
My manager has this query. He is entering the stock details of his
phamacy.
He has 6 columns. One is "name of the distributor",
the second is "bill number or invoice number",
the third is "amount to be paid",
the fourth is "cheque number"
the fifth is whether it has been "paid" or is "unpaid". The lst coumn I
have given conditional formatting, so that if it is paid, it will show the
fonts in green and if it is unpaid, it will show the fonts in red.

Now our query is that after say about 50 rows of enteries made, he would
like to know the moment he enters the bill no in the second coulmn, if
excel
can tell that this bill no has been enetered before? Like when you enter
text
excel repeats the entry so you can come to know, but it does not do that
in
number data type. I tried entering the numbers as a text data type, but no
use ?

Dr Alok Modi MD