cant get Antivirus from XP

string wmipathstr = @"\\" + Environment.MachineName + @"\root\SecurityCenter";
ManagementObjectSearcher searcher = new ManagementObjectSearcher(wmipathstr, "SELECT * FROM AntivirusProduct");
ManagementObjectCollection mObject = searcher.Get();
if (mObject.Count == 0)
{
    wmipathstr = @"\\" + Environment.MachineName + @"\root\SecurityCenter2";
    searcher = new ManagementObjectSearcher(wmipathstr, "SELECT * FROM AntivirusProduct");
    mObject = searcher.Get();
}
if (mObject.Count > 0)
{
    foreach (ManagementObject obj in mObject)
    {
        SysInfo = "insert into [dbo].[AntiVirus]  obj["disName"].ToString() + "','" + obj["instGuid"].ToString() + "','" + obj["SgdPrdctExe"].ToString() + "','" + obj["prdctState"].ToString() + "')";
        break;
    }
}
else
{
    SysInfo = "insert into [dbo].[AntiVirus] [disName]) values('" + MA + 'No AntiVirus')";
}