I need to disable USB Interface of the win7 64bit using c#

Question

I need to bolck USB interface mouse and keyboard . but these ways only work for 32 bit and nothing work on 64 bit...
below is the solution which is working for 32 bit windows but not working 64 bit ... I need a same function which can do the same thing for 64 bit ....
//disable USB storage...
Microsoft.Win32.Registry.SetValue(@"HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\USBSTOR", "Start", 4, Microsoft.Win32.RegistryValueKind.DWord);
//enable USB storage...
Microsoft.Win32.Registry.SetValue(@"HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\USBSTOR", "Start", 3, Microsoft.Win32.RegistryValueKind.DWord);
// Diable/ enable keyboard and mouse
 [System.Runtime.InteropServices.DllImportAttribute("user32.dll", EntryPoint = "BlockInput")]  [return: System.Runtime.InteropServices.MarshalAsAttribute(System.Runtime.InteropServices.UnmanagedType.Bool)]  public static extern bool BlockInput([System.Runtime.InteropServices.MarshalAsAttribute(System.Runtime.InteropServices.UnmanagedType.Bool)] bool fBlockIt);
i can read the value on windows 64 bit but can not write the value.... 
RegistryKey registryKey = RegistryKey.OpenBaseKey(Microsoft.Win32.RegistryHive.LocalMachine, RegistryView.Registry64);
 
Console.WriteLine("registryKey" + registryKey);
 
 
registryKey = registryKey.OpenSubKey(@"SYSTEM\CurrentControlSet\Services\USBSTOR");
 Object val = registryKey.GetValue("Start");
Console.WriteLine("The val is:" + val);
here i am getting the current val which is set ...
but when i try to open in write mode...
 registryKey = registryKey.OpenSubKey(@"SYSTEM\CurrentControlSet\Services\USBSTOR", true);
and try to set a value 4 to disable it cant work...
registryKey.SetValue("Start", 4);


please help me to guide me...


thanks