Codigo Vb

Public Class Form1
Dim usuario, pass As String
Dim precio, cant, total, total2, desc, pago, vuelto As Integer
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e AsSystem.EventArgs) Handles MyBase.Load
usuario = InputBox("Nombre del Usuario:", "Validacion de Usuario", "Escriba su Nombre Aqui:")
MsgBox("Bienvenido(a), " & usuario)
MsgBox("Si sucompra es mayor a Q30 obtiene un descuento del 5% de su total")
ComboBox3.Items.Add("1 litro")
ComboBox3.Items.Add("2 litros")
ComboBox3.Items.Add("3 litros")Me.Text = ("Facturacion Perzonalizado")
Me.FormBorderStyle = Windows.Forms.FormBorderStyle.FixedToolWindow
Label2.Visible = False
Label3.Visible = False
Label4.Visible =False
Label5.Visible = False
Label6.Visible = False
Label7.Visible = False
Label8.Visible = False
ComboBox2.Visible = False
ComboBox3.Visible =False
TextBox1.Visible = False
TextBox2.Visible = False
TextBox3.Visible = False
TextBox4.Visible = False
TextBox5.Visible = False
Button2.Visible= False
Button3.Visible = False
Button5.Visible = False
End Sub

Private Sub ComboBox1_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs)Handles ComboBox1.SelectedIndexChanged
If ComboBox1.SelectedItem = "rojo" Then
Me.BackColor = Color.Red
End If
If ComboBox1.SelectedItem = "azul" ThenMe.BackColor = Color.Blue
End If
If ComboBox1.SelectedItem = "blanco" Then
Me.BackColor = Color.White
End If
If ComboBox1.SelectedItem = "amarillo"Then
Me.BackColor = Color.Yellow
End If
If ComboBox1.SelectedItem = "gris" Then
Me.BackColor = Color.Gray
End If
Label2.Visible = True...