If you didn't see my post in your other thread, I'll copy and paste it here:
If you're looking at prebuilts, you're probably going to end up with a computer with an AMD A6, which would probably run TF2, though maybe not very well on high settings.
This on the other hand, you could buy these parts off newegg.com (I'm assuming you're american) and have a pretty decent machine. If I recall, that graphics card is capable of playing Battlefield 3, though don't hold it against me if it doesn't.

Tom's hardware has this to say about the CPU:
It turns out that the budget-oriented Sandy Bridge-based Pentium family performs very well in games. Specifically, Intel's $70 Pentium G630 beat the FX-4100, -6100, and -8120 in our recent sub-$200 CPU gaming comparison. In fact, it finished right on par with the Phenom II X4 955.
As a result, Intel displaces AMD at the bottom rung of our recommendation list yet again this month. There's not much else to add, except that if you consider the Phenom II X4 to be a capable gaming CPU, Intel's Pentium G630 is just as viable.
and this to say about the graphics card:
At the same price, AMD's Radeon HD 6770 outperforms the company's newer Radeon HD 7750. The only problem is that the old card uses twice as much power in the process. The Radeon HD 7750 is the fastest graphics card you can get right now that doesn't require a auxiliary power input; it draws all that it needs from a 16-lane PCIe slot.
The case (In my opinion) looks better than the glossy plastic on many of the HP desktops that you're going to be looking at in that price range.