Newegg and Tigerdirect have prebuilt PCs. I did a short summary link set here to compare graphics, cpus: http://answers.yahoo.com/question/index;... When you build your own, or custom order, you can get one with a good power supply and motherboard. Upgrading a motherboard causes Windows license issues, needs a re-install, and is called counterfeit unless you buy a new set of disks.
$500 is a bit too low. The new PS4 has graphics equivalent to an HD 7850 and cpu equivalent to AMD FX-8100. Going on the low price range of computers does not get enough performance.
Entry level for 2013 is about HD 7750 graphics and FX-4300 CPU(or Intel i3-3220). 12 currently at Newegg including OPEN BOX to $800 http://www.newegg.com/Product/ProductLis... You can also look at tigerdirect. GPU Hierarchy, and minimum is tier 11 with the HD 7750, which is why Newegg is such a small list http://www.tomshardware.com/reviews/gami... The frame rates of games depend about 60% on GPU, 30% on CPU, 10% on RAM and other but the weakest link will determine the final results.
Can email me if after you have looked around. You can buy a cheaper PC and upgrade it also with a new power supply and graphics card.
Fry's Electronics or Best Buy... At least last time I remember being there...
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.