Try this...
Sub RemoveDuplicates()
' Sort by column 1...
Cells.Sort Key1:=Range("A1")
' Determine number of rows used in worksheet...
totalrows = ActiveSheet.UsedRange.Rows.Count
' Initialize counter...
Count = 1
' Step through the rows in reverse order with "Step -1".
For Row = totalrows To 2 Step -1
' Check value in column 1 to see if it is the same
' as the previous row...
If Cells(Row, 1).Value = Cells(Row - 1, 1).Value Then
' Found a dupe. Delete it and increment counter
Rows(Row).Delete
Count = Count + 1
Else ' Not a duplicate. This is a new record, so...
' put the counter value in the spreadsheet for
' the previous record:
Cells(Row, 3).Value = Count
Count = 1 ' reset counter for new record
End If
Next Row
' Don't forget last record (which is actually first)...
Cells(1, 3).Value = Count
End Sub