Windows 7 Can't install drivers in device manager.

Yesterday I did a re-install of Windows 7 Ultimate on my PC due to a crash caused by video drivers. (That's another topic). From my previous install I learned that I had no sound and my video display wasn't right and learned that I had to download drivers from Microsoft and install them to get my sound to work and monitor to display properly. For some reason I am now unable to do that. I downloaded the appropriate drivers, went into device manger and attempted to update drivers (as administrator). I get the following message: "The best driver software for your device is already installed". My problem with audio is that the current driver doesn't work and I need the older driver to get sound. With video it's a similar situation. Does anyone have any ideas as to why device manager "thinks" it knows better than I do. Or how I can install the appropriate drivers? Thanks.