Andrea, este código es para Win 9x nunca lo probé con Xp, pero podés probar
'Estas son las APIS para detectar la barra , ocultarla y bloquear la combinación de control alt del
'este cdigo pegalo en un Modulo
Private Declare Function FindWindow Lib "user32" Alias "FindWindowA" (ByVal lpClassName As String, ByVal lpWindowName As String) As Long
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
Private Declare Function SetWindowPos Lib "user32" _
(ByVal hwnd As Long, ByVal hWndInsertAfter As Long, _
ByVal X As Long, ByVal y As Long, ByVal cx As Long, _
ByVal cy As Long, ByVal wFlags As Long) As Long
Private Const SWP_HIDEWINDOW = &H80
Private Const SWP_SHOWWINDOW = &H40
Public Function HideTaskBar() As Boolean
Dim lRet As Long
Dim lRet2 As Long
lRet = FindWindow("Shell_traywnd", "")
If lRet > 0 Then
lRet = SetWindowPos(lRet, 0, 0, 0, 0, 0, SWP_HIDEWINDOW)
HideTaskBar = lRet > 0
End If
lRet2 = FindWindow(vbNullString, "Program Manager")
If lRet2 > 0 Then
MsgBox "ocultado el program"
lRet2 = SetWindowPos(lRet2, 0, 0, 0, 0, 0, SWP_HIDEWINDOW)
End If
End Function
Public Function ShowTaskBar() As Boolean
Dim lRet As Long
Dim lRet2 As Long
lRet = FindWindow("Shell_traywnd", "")
If lRet > 0 Then
lRet = SetWindowPos(lRet, 0, 0, 0, 0, 0, SWP_SHOWWINDOW)
ShowTaskBar = lRet > 0
End If
lRet2 = FindWindow(vbNullString, "Program Manager")
If lRet2 > 0 Then
lRet2 = SetWindowPos(lRet2, 0, 0, 0, 0, 0, SWP_SHOWWINDOW)
End If
End Function
Sub main()
Form1.Show 1
End Sub
'El siguiente codigo pegalo en el Form1
Private Sub Command1_Click()
' aquí se puede poner una rutina de password
'si es correcto se ejecutan las lineas
'siguiente, de lo contrario Exit Sub
Me.Caption = "Inhabilitar el sistema"
a = ShowTaskBar()
Dim X As Long
X = SystemParametersInfo(97, False, CStr(1), 0)
End Sub
Private Sub Command2_Click()
a = HideTaskBar()
Dim X As Long
X = SystemParametersInfo(97, True, CStr(1), 0)
Me.Caption = "Sistema Inhabilitado"
End Sub
Obviamente te faltan algunos pasos, como el de estirar el Form1, para que ocupe toda la pantalla, que sea TOPMOST y que al ingresar la clave correcta en un textbox vuelva a habilitar todo.
Pero eso lo sabrás hacer, seguramente.
Mucha suerte.