Key Block

[TT(n)]

Here is an update I made from that example.
This really doesnt block the combo, but I have been able to modify this so you can change the ctl alt delete combo. Yes it exists in VB.NET.
Your on your own, if you need to block the combo.

Imports System.Drawing
Imports System.Threading
Imports System.Reflection
Imports System.Runtime.InteropServices
Imports Microsoft.Win32
Friend Class Form1
    Inherits System.Windows.Forms.Form

' Windows Form Designer generated code

 Public Structure KBDLLHOOKSTRUCT
        Public vkCode As Integer
        Public scanCode As Integer
        Public flags As Integer
        Public time As Integer
        Public dwExtraInfo As Integer
    End Structure
    Public Delegate Function KeyboardHookDelegate(ByVal Code As Integer, ByVal wParam As Integer, ByRef lParam As KBDLLHOOKSTRUCT) As Integer
    <MarshalAs(UnmanagedType.FunctionPtr)> Private callback As KeyboardHookDelegate
    Public KeyboardHandle As Integer
    Const HC_ACTION As Integer = 0
    Const WH_KEYBOARD_LL As Integer = 13&
    Const SPI_SCREENSAVERRUNNING = 97
    Const VK_ESCAPE As Integer = &H1B
    Const VK_SHIFT As Integer = &H10
    Const VK_CONTROL As Integer = &H11
    Const VK_MENU As Integer = &H12
    Const VK_DELETE As Integer = &H2E
    Const VK_TAB As Integer = &H9 
    Const VK_LWIN As Integer = &H5B
    Const VK_RWIN As Integer = &H5C 
    Private Declare Function GetAsyncKeyState Lib "user32" (ByVal vKey As Integer) As Integer
    Private Declare Function SystemParametersInfoByVal Lib "user32" Alias "SystemParametersInfoA" (ByVal uAction As Integer, ByVal uParam As Integer, ByVal lpvParam As Object, ByVal fuWinIni As Integer) As Integer
    Public Declare Function SetWindowsHookEx Lib "user32" Alias "SetWindowsHookExA" (ByVal idHook As Integer, ByVal lpfn As KeyboardHookDelegate, ByVal hmod As Integer, ByVal dwThreadId As Integer) As Integer
    Private Declare Function CallNextHookEx Lib "user32" (ByVal hHook As Integer, ByVal nCode As Integer, ByVal wParam As Integer, ByVal lParam As KBDLLHOOKSTRUCT) As Integer
    Public Declare Function UnhookWindowsHookEx Lib "user32" (ByVal hHook As Integer) As Integer
    Dim clt() As Process = Process.GetProcessesByName("taskmgr")
    Dim t As New Thread(AddressOf KillTask)


    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        On Error Resume Next
        If RadioButton1.Checked = True Then
            Call SystemParametersInfoByVal(SPI_SCREENSAVERRUNNING, 1, "1", 0)
        Else
            HookKeyboard()
        End If
    End Sub
    Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
        On Error Resume Next
        If RadioButton1.Checked = True Then
            Call SystemParametersInfoByVal(SPI_SCREENSAVERRUNNING, 0, "1", 0)
        Else
            t.Abort()
            UnhookKeyboard()
        End If
    End Sub
    Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click
        On Error Resume Next
        Dim regKey As RegistryKey
        Dim regVal As String = ""
        Registry.CurrentUser.CreateSubKey("Software\Microsoft\Windows\CurrentVersion\Policies\System")
        regKey = Registry.CurrentUser.OpenSubKey("Software\Microsoft\Windows\CurrentVersion\Policies\System", True)
        regKey.SetValue("DisableTaskMgr", 1)
        regKey.Close()
        regKey = Registry.CurrentUser.OpenSubKey("Control Panel\Desktop", True)
        regVal = regKey.GetValue("ScreenSaveActive")
        If regVal = "1" Then
            regKey.SetValue("ScreenSaveActive", "0")
        End If
        regKey.Close()
    End Sub
    Private Sub Button4_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button4.Click
        On Error Resume Next
        Dim regKey As RegistryKey
        Dim regVal As String
        Registry.CurrentUser.CreateSubKey("Software\Microsoft\Windows\CurrentVersion\Policies\System")
        regKey = Registry.CurrentUser.OpenSubKey("Software\Microsoft\Windows\CurrentVersion\Policies\System", True)
        regKey.SetValue("DisableTaskMgr", 0)
        regKey.Close()
        regKey = Registry.CurrentUser.OpenSubKey("Control Panel\Desktop", True)
        regVal = regKey.GetValue("ScreenSaveActive")
        If regVal = "0" Then
            regKey.SetValue("ScreenSaveActive", "1")
        End If
        regKey.Close()
    End Sub
    Private Sub Form1_Closed(ByVal sender As Object, ByVal e As System.EventArgs) Handles MyBase.Closed
        On Error Resume Next
        If RadioButton1.Checked = True Then
            Call SystemParametersInfoByVal(SPI_SCREENSAVERRUNNING, 0, "1", 0)
        Else
            t.Abort()
            UnhookKeyboard()
        End If
    End Sub
    Public Sub KillTask()
        On Error Resume Next
        Do
            Dim clt() As Process = Process.GetProcessesByName("taskmgr")
            For Each p As Process In clt
                p.Kill()
            Next
            System.Threading.Thread.Sleep(1)
        Loop
    End Sub
    Public Function IsHooked(ByRef Hookstruct As KBDLLHOOKSTRUCT) As Boolean
        On Error Resume Next
         'Capture combos
        If (Hookstruct.vkCode = VK_DELETE) And CBool(GetAsyncKeyState(VK_MENU) And &H8000) And CBool(GetAsyncKeyState(VK_CONTROL) And &H8000) Then
            t.Start()
            Return True
        End If
        If (Hookstruct.vkCode = VK_ESCAPE) And CBool(GetAsyncKeyState(VK_CONTROL) And &H8000) And CBool(GetAsyncKeyState(VK_SHIFT) And &H8000) Then
            t.Start()
            Return True
        End If

         'Capture your Alt + Tab combo here on your own, and return true

         'Capture all your winlogo combos, and return true for each if/end if.

        Return False
    End Function
    Public Sub HookKeyboard()
        callback = New KeyboardHookDelegate(AddressOf KeyboardCallback)
        KeyboardHandle = SetWindowsHookEx(WH_KEYBOARD_LL, callback, Marshal.GetHINSTANCE([Assembly].GetExecutingAssembly.GetModules()(0)).ToInt32, 0)
    End Sub
    Public Sub UnhookKeyboard()
        If (Hooked()) Then
            Call UnhookWindowsHookEx(KeyboardHandle)
        End If
    End Sub
    Private Function Hooked()
        Hooked = KeyboardHandle <> 0
    End Function
    Public Function KeyboardCallback(ByVal Code As Integer, ByVal wParam As Integer, ByRef lParam As KBDLLHOOKSTRUCT) As Integer
        If (Code = HC_ACTION) Then
            If (IsHooked(lParam)) Then
                Return 1
            End If
        End If
        Return CallNextHookEx(KeyboardHandle, Code, wParam, lParam)
    End Function