Hmm I have used it for processor information perfectly fine, and I had the same error that I have now, only thing is, I don't know how I fixed it

Here is my code and the error:
VB Code:
  1. Dim query1 As New Management.SelectQuery("Win32_PhysicalMedia")
  2.         Dim search1 As New Management.ManagementObjectSearcher(query1)
  3.         Dim info1 As New Management.ManagementObject
  4.         For Each info1 In search1.Get()
  5.             RichTextBox1.Text = RichTextBox1.Text & vbNewLine & "Disks: " & info1("caption").ToString() ' & " - " & info("Status").ToString()
  6.         Next
Error: System.NullReferenceException was unhandled
Message="Object reference not set to an instance of an object."

I wonder what is the problem....?