It would help if you could tell us the make and model of the computer you are having the problem with, if it is a self-build, the make and model of the motherboard.
In general, the best place to get drivers of this sort is from either the computer manufacturer's web-site or the motherboard manufacturer's site. This way you normally get the latest drivers.
The most likely causes of your problems are that either the drivers didn't uninstall properly, or the new ones haven't installed properly. I would be inclined to do the uninstall again, shut down the computer then start it again - as opposed to using 'Re-start', and only then do the re-install.