sorry about that I had used the conversion (C# to VB) tool from here http://www.developerfusion.co.uk/utilities/convertcsharptovb.aspx

Just replace the older one with

Protected Sub TreeView1_TreeNodeExpanded(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.TreeNodeEventArgs) Handles TreeView1.TreeNodeExpanded

        If e.Node.Parent Is Nothing Then
            For Each node As TreeNode In (CType(sender, TreeView)).Nodes
                If Not (node.Equals(e.Node)) Then
                    node.Collapse()
                End If
            Next
            Return
        End If

        Dim tn As TreeNode = e.Node.Parent
        For Each node As TreeNode In tn.ChildNodes
            If Not (node.Equals(e.Node)) Then
                node.Collapse()
            End If
        Next

        If (e.Node.Depth = 1) Then

        End If

    End Sub

Regarding the new layout. Can you explain a little more of what you are trying to do?

Thanks