Need help on VBA

[arnelgp]

here you try this

Option Explicit


Private Sub Worksheet_Change(ByVal Target As Range)
Dim i As Integer, dt1 As Date, dt2 As Date
Dim j As Integer, k As Integer
Application.EnableEvents = False
If Left$(Target.Address, 2) = "$B" Then
    If InStr(1, Target.Address, ":") = 0 Then
        If Val(Range("$A$" & Target.Row)) <> 0 And Val(Target) <> 0 Then
            dt1 = Range("$A$" & Target.Row).Value
            dt2 = Target.Value
            i = DateDiff("h", dt1, dt2)
            j = DateDiff("h", #12:00:00 AM#, dt1) + 4
            For k = j To j + i
                Cells(Target.Row, k) = 1
            Next
        End If
    End If
End If
Application.EnableEvents = True
End Sub