Sub searchandrep()
Dim WS_Count As integer
Dim i As integer

WS_Count = ActiveWorkbook.Worksheets.Count


For i = 2 To WS_Count


activeworkbook.Worksheets(i).rows(1).Replace _
 What:="toreplacetext", Replacement:="replacetxt"+cstr(i), _
 SearchOrder:=xlByrows, MatchCase:=True


next i

end sub