急求解决web安装服务的问题

比如说别人已经写好了个服务并且可以顺利安装，当安装后我把那个服务代码copy了一遍 
改了点点的里面可以变动的东西，再次安装的时候系统说已经改服务应经是最新本版？
 请教下，当我再次安装该服务不卸载以前的服务的时候 我是不是要修改下代码中的注册表？        private string GetInstallPath()
        {
            string InstallPath = string.Empty; 
            RegistryKey pregkey;
            RegistryKey HRMPTKey;
            pregkey = Registry.LocalMachine.OpenSubKey("Software", true);
            if (pregkey == null)
            {
                throw new Exception("键值不存在");
            }
            else
            {
                try
                {
                   
                     HRMPTKey = pregkey.OpenSubKey("HRMPT", true);
                    if (null != HRMPTKey)
                    {
                        InstallPath = HRMPTKey.GetValue("ProductPath").ToString();
                        HRMPTKey.Close();
                    }
                } 
                catch (Exception ex)
                {
                    throw new Exception("设置注册表出错!");
                }
                finally
                {
                }
            }            pregkey.Close();
            return InstallPath;
        }