So you.....
1. Uninstalled GFX driver
2. Shut down and swapped cards
3. Installed new GFX driver
If not, at this point I'd ....
1. Uninstalled all GFX drivers and related programs and reboot
2. Clean out registry of all references to GFX drivers and reboot
3. Shut down and swap cards
4. Install new (latest) GFX driver