Why it doe'nt reboot?

[sebs]

I want my program to reboot my computer and my code:

Private Sub Command1_Click()
Dim retval As Long  ' return value
retval = ExitWindowsEx(EWX_FORCE Or EWX_REBOOT, 0)
End Sub

my module:

Public Declare Function ExitWindowsEx Lib "user32.dll" 
(ByVal uFlags As Long, ByVal dwReserved As Long) As Long

i try it with a look up
and my return value(retval) = 1, so it's suppose to reboot but it's not, WHY????????