Mute WebBrowser control

// Constants
private const int FEATURE_DISABLE_NAVIGATION_SOUNDS = 21;
private const int SET_FEATURE_ON_THREAD = 0x00000001;
private const int SET_FEATURE_ON_PROCESS = 0x00000002;
private const int SET_FEATURE_IN_REGISTRY = 0x00000004;
private const int SET_FEATURE_ON_THREAD_LOCALMACHINE = 0x00000008;
private const int SET_FEATURE_ON_THREAD_INTRANET = 0x00000010;
private const int SET_FEATURE_ON_THREAD_TRUSTED = 0x00000020;
private const int SET_FEATURE_ON_THREAD_INTERNET = 0x00000040;
private const int SET_FEATURE_ON_THREAD_RESTRICTED = 0x00000080;

// Necessary dll import
[DllImport("urlmon.dll")]
[PreserveSig]
[return:MarshalAs(UnmanagedType.Error)]
static extern int CoInternetSetFeatureEnabled(
int FeatureEntry,
[MarshalAs(UnmanagedType.U4)] int dwFlags,
bool fEnable);

......

// You can call the CoInternetSetFeatureEnabled like this:
CoInternetSetFeatureEnabled(FEATURE_DISABLE_NAVIGATION_SOUNDS, SET_FEATURE_ON_PROCESS, true);