The Wal-Mart version is a very old version intended for people who are not interested in spending $20 on the latest version.
I realize that not all regions have stores that carry the full-featured Marine Aquarium 2 product (CompUSA, MicroCenter, Fry's).
All the problems you describe affect high-end computers running the old version of the Aquarium.
I would definitely upgrade at SereneScreen.com to the newest version which is 2.0 MD. It has 6 more fish and a Starfish, an awesome control panel, Widescreen/Dual monitor support, and CPU throttling controls to run on any kind of motherboard/CPU combination. It also knocks out that infinite sound bug.
Welcome to the forums and welcome fellow A7N8X user.