|"Did you install the drivers for the Intel Z77 motherboard chipset?"|
You MUST do that. They're NOT built into XP.
The Switchable Graphics feature is for Windows 7 only.
Lucid Virtu MVP - Windows 7 only
Info and video about Virtu MVP features here:
The Intel Z77 main chipset supports a form of Hybrid video - both the onboard video and the video on a card in a PCI-E X16 slot working at the same time.
You may need to change a setting or two in the bios Setup.
Under Peripherals in the bios Setup
Init Display First
that may NOT work fine as is when you have a PCI-E X16 card installed
set that to PEG
That may work fine as is.
If you want to disable the onboard video, set that to Disable.