First, you need to set the TextBox's MultiLine Property to True
Code:
Text1.MultLine = True
Second, in a textbox you need both a Carriage Return & a Line Feed. So, use one of these
Code:
Text1.Text = "First Line" & vbCrLF & "Second Line"
'or
Text1.Text = "First Line" & vbNewLine & "Second Line"
'or
Text1.Text = "First Line" & Chr(13) & Chr(10) & "Second Line"
I use the the Second One myself