Don't fear system BIOS, just respect it.
It never hurts to browse the menus in BIOS. When you exit BIOS, you will always be asked to save any changes you have made. If you are worried that you changed something you shouldn't have, just say NO to saving changes.
Go into the BIOS menus and find the option to disable the onboard sound (Realtek AC97). Don't do anything else. This is not difficult.
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? Thanks for any help