Vb.NET Device Unique Identifier Win10 - vb.net

Question

I'm trying to get a Device Unique Identifier in vb.net code. I have tried with
Private Function SystemSerialNumber() As String
Dim value As String = ""
Dim baseBoard As ManagementClass = New ManagementClass("Win32_BaseBoard")
Dim board As ManagementObjectCollection = baseBoard.GetInstances()
If board.Count > 0 Then
value = board(0)("SerialNumber")
If value.Length > 0 Then value = value.Substring(2)
End If
Return value
End Function
Which works on some computers but of the board doesn't have a serial number it returns "Default String" or whatever they put in there. Even tried with Win32_Processor and some have it and others just return "To be filled by O.E.M" lol
Also tried with,
Private Function SystemSerialNumber() As String
Dim value As String
Dim q As New SelectQuery("Win32_bios")
Dim search As New ManagementObjectSearcher(q)
Dim info As New ManagementObject
For Each info In search.Get
value = info("SerialNumber").ToString
Return value
Next
End Function
But its the same some devices have it some don't and just returns default string.
So I'm now trying is:
Private Function SystemSerialNumber() As String
Dim value As String
value = Windows.System.Profile.SystemIdentification.GetSystemIdForPublisher()
End Function
But I'm having trouble referencing to it. I tried Imports Windows.System but it just gives the error it cant be found.
As a side note I'm using this program in tablets with windows10, laptops, and desktops.
UPDATE: I'll be using as suggested by Heinzi. Thanks!
Also changed variable names to be more accurate.
Private Function NetworkAdapterMacAddress() As String
Dim McAddress As String
Dim netadapter As ManagementClass = New ManagementClass("Win32_NetworkAdapterConfiguration")
Dim mo As ManagementObject
Dim adapter As ManagementObjectCollection = netadapter.GetInstances()
For Each mo In adapter
If mo.Item("IPEnabled") = True Then
McAddress = mo.Item("MacAddress").ToString()
Return McAddress
End If
Next
End Function

Answer 1

Well, there is no guaranteed ID that identifies every PC out there uniquely (fortunately, I might add. Privacy is a good thing).
You best bets are probably
the MAC of the network adapter (changes when the network adapter is replaced) or
the Windows Computer SID (changes when Windows is reinstalled).
Oh, and on a philosophical note, you might want to ponder on the Ship of Theseus.