try: put in sheet's code module

Private Sub Worksheet_Change(ByVal Target As Range)
If ActiveCell.Column = 1 Then
If Target = "X" Then
ActiveCell.Offset(-1, 1) = Date ' date in column B
'ActiveCell.Offset(-1, 2) = Date ' date in column C
'ActiveCell.Offset(-1, 3) = Date ' date in column D
ActiveCell.Offset(-1, 1).Columns.AutoFit ' remember to chage this if u
change date column
End If
End If
End Sub