Finding Duplicate or Unique value in Microsoft Excel 2010 is way easier than previous versions. Just using the Conditional Formating will do the job. To do this first
Select the desire range you want to find any duplicate or unique cell value.
Next click on the Conditional Formating button in the home tab of the ribbon, and select New Rule…
Select “Format only unique or duplicate values”
Select either duplicate or unique values from the dropdown list and then format the the cell the way you want.
Now whenever you put any duplicate/unique cell value in that range your format will be automatically applied on that cell.