RegistryKey.DeleteSubKey Method (String)

using System;
using Microsoft.Win32;

class RegKeyDel
{
    static void Main()
    {
        // Create a subkey named Test9999 under HKEY_CURRENT_USER.
        RegistryKey test9999 =
            Registry.CurrentUser.CreateSubKey("Test9999");
        // Create two subkeys under HKEY_CURRENT_USER\Test9999. The 
        // keys are disposed when execution exits the using statement.
        RegistryKey testName = test9999.CreateSubKey("TestName");
        RegistryKey testSettings = test9999.CreateSubKey("TestSettings");

        // Create data for the TestSettings subkey.
        testSettings.SetValue("Language", "French");
        testSettings.SetValue("Level", "Intermediate");
        testSettings.SetValue("ID", 123);

        // delete the subkey "TestName"
        test9999.DeleteSubKey("TestName");
        // delete everything under and including "Test9999"
        Registry.CurrentUser.DeleteSubKeyTree("Test9999");
    }
}