C#

using System;
using Microsoft.Win32;
using System.Security.Permissions;

namespace RegExlorer
{
  class RegExplorer
  {
    public static void Main()
    {
      try
      {
        RegistryPermission f = new RegistryPermission(
          RegistryPermissionAccess.Read, 
          "\\cosette\\HKEY_CURRENT_USER\\Volatile Environment\\0");
        
        RegistryKey remoteUserHive;
        RegistryKey volatileEnvKey;
        object myObj;

        // try to open HKEY_CURRENT_USER hive on remote machine
        remoteUserHive = RegistryKey.OpenRemoteBaseKey(RegistryHive.CurrentUser, "COSETTE");
        if (remoteUserHive != null)
        {
          // try to open (HKEY_CURRENT_USER\)Volatile Enviornment" hive on remote machine
          volatileEnvKey = remoteUserHive.OpenSubKey("Volatile Environment");
          if (volatileEnvKey != null)
          {
            // get value
            myObj = volatileEnvKey.GetValue("LOGONSERVER");

            // print the result out to the screen
            Console.WriteLine(myObj.ToString());
          }
        }
      }
      catch(Exception e)
      {
        Console.WriteLine(e.Message);
      }

      // wait for a key stroke
      Console.ReadLine();
    }
  }
}