How to Use SpUserToken in SharePoint 2007 or SharePoint 2010

using System; using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using Microsoft.SharePoint;
using System.Security;
public partial class WebUserControl : System.Web.UI.UserControl
{
protected void Page_Load(object sender, EventArgs e)
{
SPUserToken sToken = SPContext.Current.Site.SystemAccount.UserToken;
using (SPSite site = new SPSite(http://vlnrm:100/, sToken))
{
using (SPWeb objWeb = site.OpenWeb())
{
SPQuery query = new SPQuery();
query.Query = "<OrderBy><FieldRef Name='ID' Ascending='False' /></OrderBy>";
SPList lst = objWeb.Lists["My Links"];
SPListItemCollection myColl = lst.GetItems(query);
if (myColl.Count > 0)
{
this.Controls.Add(new LiteralControl("<Table width='100%' bgcolor='Aqua'>"));
this.Controls.Add(new LiteralControl("<Tr>"));
this.Controls.Add(new LiteralControl("<Td>"));
this.Controls.Add(new LiteralControl("<Strong>"));
this.Controls.Add(new LiteralControl("Link Name"));
this.Controls.Add(new LiteralControl("</Strong>"));
this.Controls.Add(new LiteralControl("</Td>"));
this.Controls.Add(new LiteralControl("</Tr>"));
foreach (SPListItem item in myColl)
{
string strHyperLInkTitle = string.Empty;
string strHyperLinkURL = string.Empty;
strHyperLInkTitle = item["HyperLinkTitle"].ToString();
strHyperLinkURL = item["URL"].ToString();
this.Controls.Add(new LiteralControl("<Tr>"));
this.Controls.Add(new LiteralControl("<Td>"));
this.Controls.Add(new LiteralControl("<A href='"+strHyperLinkURL+"'>"+strHyperLInkTitle+"</A>"));
this.Controls.Add(new LiteralControl("</Td>"));
this.Controls.Add(new LiteralControl("</Tr>"));
}
this.Controls.Add(new LiteralControl("<Table>"));
}
}
}
}
}