Private Declare Function SystemParametersInfo Lib "user32" _
Alias "SystemParametersInfoA" (ByVal uAction As Long, _
ByVal uParam As Long, ByVal lpvParam As Any, ByVal fuWinIni As Long) As Long

' Отключить Ctrl+Alt+Del
SystemParametersInfo 97, True, vbNullString, 0
' Включить Ctrl+Alt+Del
SystemParametersInfo 97, False, vbNullString, 0