try
            {
                using (RegistryKey key = Registry.LocalMachine.OpenSubKey("HKEY_USERS\\"+sidString+"\\Software\\SAMP"))
                {
                    if (key != null)
                    {
                        Object o = key.GetValue("PlayerName");
                        if (o != null)
                        {
                            String playerName = new String(o as String);  //"as" because it's REG_SZ...otherwise ToString() might be safe(r)
                            txtPlayerName.Text = playerName;
                        }
                    }
                }
            }
            catch (Exception ex)  //just for demonstration...it's always best to handle specific exceptions
            {
                //react appropriately
            }