Well, I wouldn't call this a "solution," but I got the system restore disks for that model of DV9700 and put The Package on The Machine.
When I checked the device manager, there it was: "Standard VGA Driver!"
Answer: that model of HP Pavilion has a brain-dead GPU. Shouldn't have wasted my money on it.
Back to the FrankenPC. Good thing I'm a pack rat.
