Me.Chart1.Series.Add(Form3.TextBox6.Text)
Me.Chart1.Series.Add(Form3.TextBox17.Text)
Me.Chart1.Series.Add(Form3.TextBox23.Text)
Me.Chart1.Series.Add(Form3.TextBox29.Text)
Me.Chart1.Series.Add(Form3.TextBox35.Text)
Suggestion: Use proper names for your textboxes that actually reflect the content of the box. Using the default VS generated names can lead to obscure bugs in future.