Highlight the entire column and click Data-Validation
Under "Allow" select Custom
Under "Formula" enter the following
=COUNTIF(A:A,A1)<=1
Replace all A's with the column selected. i.e. enter this formula for
column C...
=COUNTIF(C:C,C1)<=1

"Vijay Kotian" wrote:

In one of the column the same data should not be repeated while
coping and should prompt or give a error message. OR

How can i ensure that the same data is not repeated while coping
in a particular column? OR ANY OTHER WAY TO KEEP CONTROL ON SAME SET OF DATA
IN A PARTICULAR COLUMN Pl help.