using Microsoft.Win32;

try
{
	//Open subkey
	RegistryKey r = Registry.CurrentUser.OpenSubKey(@"Software\MyApp",true);
	object oMyAppVersionValue = null;

	//If subkey or name/value registry key pair does not exists
	if (r == null || (r != null && r.GetValue("Version", null) == null))
	{
		if (r == null)
		{
			//Create subkey
			r = Registry.CurrentUser.CreateSubKey(@"Software\MyApp");
		}
		//Create name/value registry key pair
		r.SetValue("Version", "1.0.0", RegistryValueKind.String);
		//Read value for "Version"
		oMyAppVersionValue = r.GetValue("Version", null);
	}
	else
	{
		//If subkey and name/value registry key pair exists
		//Read value for "Version"
		oMyAppVersionValue = r.GetValue("Version", null);
	}
	if (oMyAppVersionValue != null && oMyAppVersionValue is String)
	{
		//Show the value
		MessageBox.Show((String)oMyAppVersionValue, "MyApp Version");
	}
	//Close the key and flush changes.
	r.Close();
	
	//Delete HKEY_CURRENT_USER\Software\MyApp (including subkeys)
	Registry.CurrentUser.DeleteSubKeyTree(@"Software\MyApp");
}
catch (Exception E)
{
	MessageBox.Show(E.Message);
}