By the way you only need to create one instance of the Random class and call it's Next method to create another random number.

vb.net Code:
  1. Public Class Form1
  2.  
  3.     Dim rand As New Random
  4.  
  5.     Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
  6.  
  7.         'Generate random number between 1 and 10
  8.         Dim randomNumber1 As Integer = rand.Next(1, 11)
  9.         'Generate random number between 50 and 100
  10.         Dim randomNumber2 As Integer = rand.Next(50, 101)
  11.         'Generate random number between 500 and 1000
  12.         Dim randomNumber3 As Integer = rand.Next(500, 1001)
  13.  
  14.         Label1.Text = "Random number1: " & randomNumber1.ToString & " Random number2: " & randomNumber2.ToString & _
  15.                       " Random number3: " & randomNumber3.ToString
  16.  
  17.     End Sub
  18. End Class