I just installed an NVIDIA GeForce 9400 GT that I had lying around to upgrade this HP Pavilion a6712f. It's running Windows 7 64-bit SP1 now. Here's what I've tried:
-Installing 295.73 and 306.97 (both are WHQL), 295.51 and 275.33, by automated process and directly opening their setup.exe.
-Extracting the setup to a different drive and installing from there.
-Deleting all NVIDIA installer references in the registry (careful not to remove ones pertaining to Windows stock itself).
-Scouring through with Driver Sweeper, CCleaner, and other various programs to remove any drivers that might still exist, both the original Intel onboard, and any ATI/AMD/NVIDIA that may have been installed over time.
-Disabled Windows Update temporarily (the service), thinking it might interfere with the setup.
-Dozens of restarts.
-Installing using the setup.exe in a headless, command-line installer.
-Letting Windows Update do its thing.
-Making sure the BIOS is set to only use the PCI-E x16 adapter for graphics, and not the onboard.
-Reseating the GPU.
-Disabling antivirus programs.
-Checking the HP website for chipset or other motherboard drivers - none existed, besides random BIOS updates which I'm hesitant to apply.
-Uninstalling the video adapter from the device manager, and forcing it to "update" from the disk, at the display directory.
I'm literally scratching my head at this point and I haven't the slightest clue what to do. Any insight?
By updating the BIOS to the latest version available on HP's website (5.43) and by telling it to use the "PCI" graphics adapter as forced (rather than Onboard as the post above, or PCI-E x16 like I was doing), the NVIDIA Graphics Driver and Updater were able to install. PhysX failed to, but that doesn't matter.