How to reconfigure code to output specific values rather than collection?

I currently this code on my app that works great to loop through a page and grab the label of an input value of a form and then print the value to a rich text box.

I am now trying to revamp the code to give me the ID the value if the label contains a specific name.

For instance if the label before the input field contains the word Username then I want the application to output the ID of the input field rather than just everything that has a label.

Here is my current code:

Dim web As HtmlAgilityPack.HtmlWeb = New HtmlWeb()

Dim doc As HtmlAgilityPack.HtmlDocument = web.Load("http://shaggybevo.com/board/register.php%22)

Dim nodes As HtmlNodeCollection

' Keeps track of the labels by the associated control id

Dim labelText As New System.Collections.Generic.Dictionary(Of String, String)

' First, get the labels

nodes = doc.DocumentNode.SelectNodes("//label")

If nodes IsNot Nothing Then

For Each node In nodes

If node.Attributes.Contains("for") Then

Dim sFor As String

' Extract the for value

sFor = node.Attributes("for").Value

' If it does not exist in our dictionary, add it

If Not labelText.ContainsKey(sFor) Then

labelText.Add(sFor, node.InnerText)

End If

End If

Next

End If

nodes = doc.DocumentNode.SelectNodes("//input")

Dim sbText As New System.Text.StringBuilder(500)

If nodes IsNot Nothing Then

For Each node In nodes

' See if this input is associated with a label

If labelText.ContainsKey(node.Id) Then

' If it is, add it to our collected information

sbText.Append("Label = ").Append(labelText(node.Id))

sbText.Append(", Id = ").Append(node.Id)

sbText.AppendLine()

End If

Next

End If

RichTextBox1.Text = sbText.ToString