How to disable Windows OS in C# Application?

There is a way to do it, but I would make a registry back up first, this is totally untested and with out warranty and all that stuff. But if you drill down to: HKEY_USER S-1-5-21-1960408961-15639835344-1060284298-1004 SOFTWARE MICROSOFT CURRENTVERSION POLICIES SYSTEM Again I am not sure if key ‘S-1-5-21-1960408961-15639835344-1060284298-1004’ is common to all systems. Here you will find a key called "DisableTaskmgr" Edit this key and change the value from a zero to a 1 Exit Regedit and you will find when you attempt the infamious "Ctrl+Alt+Delete" key combination a messagebox will popup advising: "Task Manager hse been disabled by your administrator." Just be careful please

hi i think that u may need to use API functions................they have some abilities to deal with the kernel of the os i am not sure but try to search in that

You can't disable it but you can control what keys has been pressed in the keyboard while your application is running.

I have found a soft which make disable those key but the author of soft don't give the source code. he only explain the way he does. That is combination of hook and subclassing. If you have researched this mechanisim, plese help me. Thanks.

I might be wrong, but that's what I heard.

This is not possible because it is a fundamental event triggered from the kernel. The only way would be to intercept the key press before the kernel, which I don't think is possible.