cjrgreen: Does the video come on at boot, when you have the new card connected to the monitor?
Leroux: When the BIOS is set to use the PCIe slot and the monitor is connected to the new video card, the booting works as always. I switch on the PC and get the booting screen, then Windows, nothing unusual (except for the low resolution in Vista).
Nothing's wrong at the BIOS level, anyway.
While it's working on the low resolution, go to AMD's site and get the latest driver bundle.
Then if you have the AMD drivers and CCC installed, uninstall them and reboot.
If Windows asks you to install drivers for your new hardware, do not do so.
Once Windows has finished barking at you about new hardware, install the driver bundle you got from AMD.
After that, you may need to reboot again.
If it comes up "Standard VGA" after you successfully installed the drivers from AMD, go into CCC (Advanced mode) and select your graphics card.