Right click-mouse over My Computer
Properties
Hardware(Tab)
Device Manager(button)
Click [+] next to System devices
right-mouse on CPU to GPU Controller
Update Driver(button)

Select Install from a list or specific location (Advanced)
Next(button)
Select Don't search. I will choose the driver to install.
Next(button)
Select PCI standard PCI-to-PCI bridge
Next(button)
Finish(button)
Reboot.