My computer has full ACPI/APM support but I still can't Hibernate or Standby using VGA adapter?

A. To use hibernate or standby the components of the system need to support power management which custom video drivers provide but the built-in VGA driver is a bare-bones VGA only driver with no power management so if you want hibernate/standby options in the Power Options control panel applet then install the correct driver for your video card.