Disable Task Manager in C# on the Vista OS

Question

Hello everyone. I'm trying to create a secure program in C#, and my hurdle is trying to prevent the user from accessing the Task Manager, to stop them from closing the program and accessing Windows. The problem I've had is all the topics online on how to do this are only texted in XP, and don't work on Vista. So I'm kind of stuck. Can anyone help me please?