Need help for Auto user name and time - excel

Question

I am using an Excel in which I need to get Auto user name and Time for two entry's example
1. If I insert a value in column 2 I need user name and time at cell "A" and "O"
2. In same Excel sheet again for the entry at Column(7) I need date and Username at cell "I" and "N"
My code working for single point and I am confuse how to use twice.
Check the code I try and advise
Private Sub Worksheet_Change(ByVal Target As Excel.Range)
Dim rng As Range, c As Range
Set rng = Application.Intersect(Target, Me.Columns(2))
If rng Is Nothing Then Exit Sub
For Each c In rng.Cells
If Len(c.Value) > 0 Then
If Len(c.Offset(0, -1).Value) = 0 Then
With c.EntireRow
.Cells(1, "A").Value = Now()
'.Cells(1, "B").Value = Date
.Cells(1, "O").Value = Environ("username")
End With
End If
End If
Set rng = Application.Intersect(Target, Me.Columns(7))
If rng Is Nothing Then Exit Sub
For Each c In rng.Cells
If Len(c.Value) > 0 Then
If Len(c.Offset(0, -1).Value) = 0 Then
With c.EntireRow
.Cells(1, "I").Value = Now()
'.Cells(1, "B").Value = Date
.Cells(1, "N").Value = Environ("username")
End With
End If
End If
Next c
End Sub

Answer 1

The problematic line is If rng Is Nothing Then Exit Sub because if Target is not in column 2 it exits sub and will never reach the second test for column 7.
So use If Not rng Is Nothing Then instead:
Private Sub Worksheet_Change(ByVal Target As Excel.Range)
Dim rng As Range, c As Range
Set rng = Application.Intersect(Target, Me.Columns(2))
If Not rng Is Nothing Then
For Each c In rng.Cells
If Len(c.Value) > 0 Then
If Len(c.Offset(0, -1).Value) = 0 Then
With c.EntireRow
.Cells(1, "A").Value = Now()
'.Cells(1, "B").Value = Date
.Cells(1, "O").Value = Environ("username")
End With
End If
End If
Next c
End If
Set rng = Application.Intersect(Target, Me.Columns(7))
If Not rng Is Nothing Then
For Each c In rng.Cells
If Len(c.Value) > 0 Then
If Len(c.Offset(0, -1).Value) = 0 Then
With c.EntireRow
.Cells(1, "I").Value = Now()
'.Cells(1, "B").Value = Date
.Cells(1, "N").Value = Environ("username")
End With
End If
End If
Next c
End If
End Sub

Answer 2

If I got it right, this is working for me:
Option Explicit
Private Sub Worksheet_Change(ByVal Target As Range)
If Target.Column = 2 Then
If Me.Cells(Target.Row, 1) = vbNullString Then Me.Cells(Target.Row, 1) = Now()
If Me.Cells(Target.Row, 15) = vbNullString Then Me.Cells(Target.Row, 15) = Environ("username")
ElseIf Target.Column = 7 Then
If Me.Cells(Target.Row, 9) = vbNullString Then Me.Cells(Target.Row, 9) = Now()
If Me.Cells(Target.Row, 14) = vbNullString Then Me.Cells(Target.Row, 14) = Environ("username")
End If
End Sub
Thought I'm not sure if you want the logging to be on the same row you are inserting data or rewrite it always on the same cell.