İşine yarar mı bilmiyorum ama şöyle bi kod buldum.Tuşları engelleyeceğine o makinede görev yöneticisini komple kapatabilirsin. Kodlar ;

///////////////// KAPATMA ///////////////
Private Sub DisableTaskManager()
Dim regkey As RegistryKey
Dim keyValueInt As String = "1"
Dim subKey As String = "Software\Microsoft\Windows\CurrentVersion\Policies\System"
Try
regkey = Registry.CurrentUser.CreateSubKey(subKey)
regkey.SetValue("DisableTaskMgr", keyValueInt)
regkey.Close()
Catch ex As Exception
MsgBox(ex.Message, MsgBoxStyle.Critical, "Registry Error!")
End Try

End Sub
///////////////////////////////////////////




//////////////// AÇMA ///////////////////
Private Sub EnableTaskManager()
Dim regkey As RegistryKey
Dim keyValueInt As String = "0" '0x00000000 (0)
Dim subKey As String = "Software\Microsoft\Windows\CurrentVersion\Policies\System"
Try
regkey = Registry.CurrentUser.CreateSubKey(subKey)
regkey.SetValue("DisableTaskMgr", keyValueInt)
regkey.Close()
Catch ex As Exception
MsgBox(ex.Message, MsgBoxStyle.Critical, "Registry Error!")
End Try

End Sub
///////////////////////////////////////////