Macro that will flag a duplicate line.

Hi,

So I am curious if there is a code for a macro that will flag a duplicate line for me. For instance,

A - B - C - D
1 123 Yes Ops
2 172 Yes Crt
3 187 No Crt
4 123 No Ops
5 187 No Crt Duplicate
6 172 No Ops
7 123 Yes Ops Duplicate

The macro (Or Formula if possible and easier) would flag any duplicate lines based on the Criteria in column A through C. I do not need the entire row to be identical, just three particular columns. In Addition, I would only want the second, third and so on tagged as a duplicate, not the original.

Thanks,
Justin

Here's my code from a more complex version...you can tweek it for your needs...

Public Sub MarkDuplicates()    'ByVal pvQry, ByVal pvDupeFld, ByVal pvMarkFld, Optional ByVal pvFld2Check)
'pvQry = query name
'pvDupeFld   = field with duplicate values
'pvMarkFld    = field to change when duplicate is found
'pvFld2Check = field to check to see if 2nd fld different than the 1st one
Dim vCurrDup, vPrevDup, vKey, vCurrFld, vAddr

on error goto ErrDupe

range("A1").select

   'set the duplicate info to search
pvDupeFld = 3
pvMarkFld = 5
pvFld2Check = 2
        
vPrevDup = "*&%"

While activecell.value <> ""
        vCurrDup = activecell.offset(0,pvDupeFld).value
        vCurrFld = activecell.offset(0,pvFld2Check).value
        vKey =  activecell.offset(0,pvFld2Check).value         
        
        If vCurrDup <> "" Then
                '-----------------------
                'MARK THE DUPES...
                '-----------------------
              If vPrevDup = vCurrDup And vPrevFld = vCurrFld Then         'mark this
                    activecell.offset(0,pvMarkFld).value = "Delete"
              End If
        End If

        vPrevDup = vCurrDup
        vPrevFld = vCurrFld
        
        activecell.offset(1,0).select   'next row
Wend
Exit Sub
ErrDupe:
MsgBox Err.Description, , "MarkDuplicates():" & Err
End Sub