Regist

 using (RegistryKey key = Registry.CurrentUser.CreateSubKey(@"Software\Microsoft\Windows\CurrentVersion\Policies\Explorer"))
            { key.SetValue("NoActiveDesktop",1,RegistryValueKind.DWord);//禁用活动桌面
 key.SetValue("ForceActiveDesktopOn", 1, RegistryValueKind.DWord);//启用活动桌面
}

RegistryKey key = Registry.CurrentUser.CreateSubKey(@"Software\Microsoft\Windows\CurrentVersion\Policies\Explorer";

key.SetValue("NoDeskTop",1,RegistryValueKind.DWord);//隐藏桌面图标
 key.SetValue("NoDeskTop", 0, RegistryValueKind.DWord);//显示桌面图标

重启计算机后生效

using (RegistryKey key = Registry.CurrentUser.CreateSubKey(@"Software\Microsoft\Windows\CurrentVersion\Policies"))
            {
                using (RegistryKey subkey=key.CreateSubKey("System"))
                { 
                    subkey.SetValue("NoDispAppearancePage", 1, RegistryValueKind.DWord);//隐藏外观
                    subkey.SetValue("NoDispBackgroundPage", 1, RegistryValueKind.DWord);//隐藏背景
}
}

            using (RegistryKey key = Registry.CurrentUser.CreateSubKey(@"Software\Policies\Microsoft"))
            {
                using (RegistryKey subkey = key.CreateSubKey("Windows"))
                {
                    using (RegistryKey rgkey = key.CreateSubKey("Control Panel"))
                    {
                        using (RegistryKey objkey = key.CreateSubKey("Desktop"))
                        {
                            objkey.SetValue("ScreenSaveActive", 0, RegistryValueKind.String);//禁止使用屏幕保护
objkey.SetValue("ScreenSaverIsSecure", 1, RegistryValueKind.String);//启用屏幕保护密码
                        }
                    }
                }
            }

 using (RegistryKey key = Registry.CurrentUser.CreateSubKey(@"Software\Microsoft\Windows\CurrentVersion\Policies\System"))
            {
                key.SetValue("DisableRegistryTools",1,RegistryValueKind.DWord);//创建值，禁用注册表
 RegistryKey rgK = Registry.CurrentUser;                rgK.DeleteSubKey(@"Software\Microsoft\Windows\CurrentVersion\Policies\System");//删除键 启用
             }

修改IE浏览器标题栏内容 
 using (RegistryKey key = Registry.CurrentUser.CreateSubKey(@"Software\Microsoft\Internet Explorer\Main"))
            {
                key.SetValue("Window Title", this.txt.Text, RegistryValueKind.String);//创建值，使用标题 
key.DeleteValue("Window Title",false);//删除设置的标题
            }

设置IE浏览器的下载路径
using (RegistryKey key = Registry.Users.CreateSubKey(@".DEFAULT\Software\Microsoft\Internet Explorer"))
            {
                key.SetValue("Download Directory",this.textBox1.Text,RegistryValueKind.String);//设置下载路径 
            }

using (RegistryKey key = Registry.CurrentUser.CreateSubKey(@"Software\Microsoft\Internet Explorer\Main"))
            {
                key.SetValue("Start Page", this.txt.Text, RegistryValueKind.String);//创建值，使用主页
}

 using (RegistryKey key = Registry.CurrentUser.CreateSubKey(@"SoftWare\Policies\Microsoft\Internet Explorer\Control Panel"))
            {
                key.SetValue("HomePage", 1, RegistryValueKind.String);//禁止修改主页
                key.SetValue("HomePage", 0, RegistryValueKind.String);//允许修改主页
            }

桌面颜色设置
 RegistryKey objkeyInfo = Registry.CurrentUser.CreateSubKey(@"Control Panel\Colors");//创建子项
 objkeyInfo.SetValue("Background", R + " " + G + " " + B, RegistryValueKind.String);

设置开机运行

//获取程序执行路径..
            string starupPath = Application.ExecutablePath;
            //class Micosoft.Win32.RegistryKey. 表示Window注册表中项级节点,此类是注册表.
            RegistryKey local = Registry.LocalMachine;
            RegistryKey run = local.CreateSubKey(@"SOFTWARE\Microsoft\Windows\CurrentVersion\Run");

            try
            {
                //SetValue:存储值的名称
                run.SetValue("WinForm", starupPath); 
                local.Close();
            }
            catch (Exception ex)
            { 
            }