话不多说，直接上菜！

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;namespace UI
{public partial class Form2 : Form{Util.Hook hook;public Form2(){InitializeComponent();this.FormBorderStyle = FormBorderStyle.None;this.WindowState = FormWindowState.Maximized;this.TopMost = true;hook = new Util.Hook();hook.Start();this.FormClosing += new FormClosingEventHandler(Form2_FormClosing);this.buttonExit.Click += new EventHandler(ButtonExit_Click);    }private void Form2_FormClosing(object sender, FormClosingEventArgs e){hook.Close();}private void ButtonExit_Click(object sender, EventArgs e){Application.Exit();}}
}

using Microsoft.Win32;
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Runtime.InteropServices;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;namespace Util
{public class Hook : IDisposable{public delegate int HookProc(int nCode, int wParam, IntPtr lParam);static int hHook = 0;public const int WH_KEYBOARD_LL = 13;HookProc KeyBoardHookProcedure;[StructLayout(LayoutKind.Sequential)]public class KeyBoardHookStruct{public int vkCode;public int scanCode;public int flags;public int time;public int dwExtraInfo;}[DllImport("user32.dll")]public static extern int SetWindowsHookEx(int idHook, HookProc lpfn, IntPtr hInstance, int threadId);[DllImport("user32.dll", CharSet = CharSet.Auto, CallingConvention = CallingConvention.StdCall)]public static extern bool UnhookWindowsHookEx(int idHook);[DllImport("user32.dll")]public static extern int CallNextHookEx(int idHook, int nCode, int wParam, IntPtr lParam);[DllImport("kernel32.dll")]public static extern IntPtr GetModuleHandle(string name);public void Start(){// 安装键盘钩子 if (hHook == 0){KeyBoardHookProcedure = new HookProc(KeyBoardHookProc);hHook = SetWindowsHookEx(WH_KEYBOARD_LL, KeyBoardHookProcedure, GetModuleHandle(Process.GetCurrentProcess().MainModule.ModuleName), 0);//如果设置钩子失败. if (hHook == 0)Close();else{RegistryKey key = Registry.CurrentUser.OpenSubKey(@"Software\Microsoft\Windows\CurrentVersion\Policies\System", true);if (key == null)//如果该项不存在的话，则创建该项key = Registry.CurrentUser.CreateSubKey(@"Software\Microsoft\Windows\CurrentVersion\Policies\System");key.SetValue("DisableTaskMgr", 1, RegistryValueKind.DWord);key.Close();}}}public void Close(){bool retKeyboard = true;if (hHook != 0){retKeyboard = UnhookWindowsHookEx(hHook);hHook = 0;}//如果去掉钩子失败. //if (!retKeyboard) throw new Exception("UnhookWindowsHookEx failed.");RegistryKey key = Registry.CurrentUser.OpenSubKey(@"Software\Microsoft\Windows\CurrentVersion\Policies\System", true);if (key != null){key.DeleteValue("DisableTaskMgr", false);key.Close();}}public static int KeyBoardHookProc(int nCode, int wParam, IntPtr lParam){if (nCode >= 0){KeyBoardHookStruct kbh = (KeyBoardHookStruct)Marshal.PtrToStructure(lParam, typeof(KeyBoardHookStruct));if (kbh.vkCode == 91) // 截获左win(开始菜单键) return 1;if (kbh.vkCode == 92)// 截获右win return 1;if (kbh.vkCode == (int)Keys.Escape && (int)Control.ModifierKeys == (int)Keys.Control) //截获Ctrl+Esc return 1;if (kbh.vkCode == (int)Keys.F4 && (int)Control.ModifierKeys == (int)Keys.Alt) //截获alt+f4 return 1;if (kbh.vkCode == (int)Keys.Tab && (int)Control.ModifierKeys == (int)Keys.Alt) //截获alt+tab return 1;if (kbh.vkCode == (int)Keys.Escape && (int)Control.ModifierKeys == (int)Keys.Control + (int)Keys.Shift) //截获Ctrl+Shift+Esc return 1;if (kbh.vkCode == (int)Keys.Space && (int)Control.ModifierKeys == (int)Keys.Alt) //截获alt+空格 return 1;if (kbh.vkCode == 241)                  //截获F1 return 1; if (kbh.vkCode == (int)Keys.Control && kbh.vkCode == (int)Keys.Alt && kbh.vkCode == (int)Keys.Delete)return 1;if ((int)Control.ModifierKeys == (int)Keys.Control + (int)Keys.Alt + (int)Keys.Delete)      //截获Ctrl+Alt+Delete return 1;if ((int)Control.ModifierKeys == (int)Keys.Control + (int)Keys.Shift)      //截获Ctrl+Shift return 1;}return CallNextHookEx(hHook, nCode, wParam, lParam);}#region IDisposable 成员public void Dispose(){Close();}#endregion}
}