Here's what I do. I find the BIOS setting to disable the onboard sound system. I usually do no bother uninstalling the drivers (your choice here) and then I follow the instructions for installing the new card.
While I take the simple router others like to peel out old drivers. Your choice.
So I ordered the Sound Blaster Audigy 2 to replace my onboard Realtek AC97. My question is, can I just uninstall it from my Device Manager??..... because I heard you had to do it through the BIOS which is something I've never tinkered with. Also, if I uninstall it through Device Manager, will it kep trying to reinstall itself through windows detecting it? Thankks for any help