To restrict windows mobile key access they are main two methods. You can replace the clock.exe in the window folder by empty application. You can change some registry values to prevent opening the clock. I will show how we can use C# to do it ----------------------------------------------------------------------------------- using Microsoft.Win32; // import Microsoft.Win32 top of the class file Dissable the clock RegistryKey hklm = Registry.LocalMachine; hklm = hklm.OpenSubKey(@"\Software\Microsoft\Clock\", true); System.Byte[] offValue = new byte[1]; offValue[0] = 0x30; hklm.SetValue("AppState", offValue); Enable the clock RegistryKey hklm = Registry.LocalMachine; hklm = hklm.OpenSubKey(@"\Software\Microsoft\Clock\", true); System.Byte[] offValue = new byte[1]; offValue[0] = 0x11; hklm.SetValue("AppState", offValue);