Paragraphs.NoLineNumber (Word)

True if line numbers are repressed for the specified paragraphs. Can be True, False, or wdUndefined.

Use the LineNumbering property of the PageSetup object to set line numbers.

With ActiveDocument.PageSetup.LineNumbering 
 .Active = True 
 .StartingNumber = 1 
 .CountBy = 1 
 .RestartMode = wdRestartContinuous 
End With 
ActiveDocument.Paragraphs(2).NoLineNumber = True