Try This:
Dim newArchive As String = _
"<archive>" & _
" <date>1-1-1993</date>" & _
" <name>bill</name>" & _
" <email>billmail@yahoo.com</email>" & _
" <time>1:39</time>" & _
" </archive>"
Dim xmldoc1 As New XmlDocument()
xmldoc1.Load("test.xml")
Dim xmldocFragment As XmlDocumentFragment = xmldoc1.CreateDocumentFragment()
xmldocFragment.InnerXml = newArchive
Dim XmlNode1 As XmlNode = xmldoc1.DocumentElement
XmlNode1.AppendChild(xmldocFragment)
xmldoc1.Save("test.xml")