public void SettingRestore(string destination, string hostfile_location, bool restroreDNS)
        {
            FileAttributes hostattributes = File.GetAttributes(hostfile_location);

            if (hostattributes.ToString().Contains(FileAttributes.Hidden.ToString()) || hostattributes.ToString().Contains(FileAttributes.System.ToString()))
            {
                File.SetAttributes(hostfile_location, FileAttributes.Normal);
            }
            try
            {
                System.IO.File.Copy(destination + "host", hostfile_location, true);                         // Copy the backup host file to that of the present host file .
            }
            catch
            {
                Thread.Sleep(1000);
                System.IO.File.Copy(destination + "host", hostfile_location, true);
            }

            if (restroreDNS)                                                                            // If dns was set to that of OpenDNS then change the dns to that of old one.
            {
                string        DNS_present;
                List <string> nullenumerable = new List <string>();
                DNS_present = File.ReadAllText(destination + "DNSBackUp.bin");


                string[] oldDNS = DNS_present.Split(new String[] { "\r\n" }, StringSplitOptions.RemoveEmptyEntries);

                using (var NWconManager = new ManagementClass("Win32_NetworkAdapterConfiguration"))
                {
                    using (var NWconfig = NWconManager.GetInstances())
                    {
                        foreach (var managementObject in NWconfig.Cast <ManagementObject>().Where(managmentObject => (bool)managmentObject["IPEnabled"]))
                        {
                            ManagementBaseObject managementBase = managementObject.GetMethodParameters("SetDNSServerSearchOrder");
                            if (managementBase != null)
                            {
                                managementBase["DNSServerSearchOrder"] = oldDNS;
                                managementObject.InvokeMethod("SetDNSServerSearchOrder", managementBase, null);
                            }
                        }
                    }
                }
                nullenumerable.Add("");
                //File.WriteAllLines(destination + "DNSBackUp.bin", nullenumerable);
                File.Create(destination + "DNSBackUp.bin");
            }
            hostattributes = File.GetAttributes(hostfile_location);

            if (hostattributes.ToString().Contains(FileAttributes.Hidden.ToString()) || hostattributes.ToString().Contains(FileAttributes.System.ToString()))
            {
                File.SetAttributes(hostfile_location, FileAttributes.Normal);
            }

            if (PasswordRequire.firstRun)
            {
                CustomerSurvey surveyObj = new CustomerSurvey();
                surveyObj.Show();
            }
        }
        void RestoreSetting_Loaded(object sender, RoutedEventArgs e)                        // Here we are checking if the DNS needs to be restored or not .
        {
            ManagementScope oMs = new ManagementScope("\\\\localhost\\root\\cimv2");

            string strQuery = "select DNSServerSearchOrder from Win32_NetworkAdapterConfiguration where IPEnabled='true'";

            ObjectQuery oQ = new ObjectQuery(strQuery);

            ManagementObjectSearcher oS = new ManagementObjectSearcher(oMs, oQ);

            ManagementObjectCollection oRc = oS.Get();

            IsolatedStorageFile dnsFile = IsolatedStorageFile.GetStore(IsolatedStorageScope.User | IsolatedStorageScope.Domain | IsolatedStorageScope.Assembly, null, null);

            foreach (ManagementObject oR in oRc)
            {
                if (!(oR.Properties["DNSServerSearchOrder"].Value == null))
                {
                    foreach (string str in (Array)(oR.Properties["DNSServerSearchOrder"].Value))
                    {
                        if (str == "208.67.222.222" || str == "208.67.220.220")               // in Case if the user is using the OpenDns already
                        {
                            currentOpenDNS = true;
                        }
                    }
                }
            }

            if (currentOpenDNS)
            {
                string DNS_present;
                DNS_present = File.ReadAllText(PasswordRequire.filePath + "DNSBackUp.bin");
                string[] oldDNS = DNS_present.Split(new String[] { "\r\n" }, StringSplitOptions.RemoveEmptyEntries);
                foreach (string dns in oldDNS)
                {
                    if (dns == "208.67.222.222" || dns == "208.67.220.220")                     // If this is true , then the user was already using openDNS
                    {
                        RestoreDNS.Visibility = System.Windows.Visibility.Hidden;
                        break;
                    }
                }
            }
        }