I would most definitely install that latest drivers, especially for a video card -- and especially for your system configuration.
You must disable the GPU on-board your APU first _before_ installing the driver for your discrete video card.
1) While computer is off, install your discrete video card (assuming it isn't installed already). Boot.
2) While your monitor is still connected to your on-board video, go into device manager and disable the on-board video itself. Shutdown, then boot.
3) Install drivers from accompanying CD. Then Install latest drivers from manufacturer's website. Undertaking both these steps will give you the option to "roll-back drivers" for troubleshooting purposes. Re-enable on-board video. Shutdown.
4)...