No Sound Device (by 2 users)

Try deleting the the AC97 from the listing of hardware in the Control Panel/System/Device Manager and rebooting.
This will force Windows to 'find' it and install some kind of driver as long as it is still functional.

If it asks for a piece of software from disk or location, browse to the folder where you have the downloaded Realtek stuff' if it finds a driver/inf file it likes, it will grab it.

BTW, I hope you are running system restore, you could have saved some time by restoring to a date prior to your program removal.