Thanks for the info and excellent reference.
My 7 year old son is playing low end video games like Roblox and Minecraft. Rigth now he is using a Dell Inspiron 531s that is about 6 years old. It has a Sempron 2600+ 2.0 GHz CPU, GeForce 9400 vid card, and 4 GB of RAM.
What I'm trying to do is build him a budget system that he can use and also I was thinking I would integrate some components that I might try to use on the next good rig; like the case, psu, ram and vid card.
Here is a link to my thread 'First Build' in Home Built Systems. http://www.tomshardware.com/forum/354450-31-first-build