PCs compatible with a new graphics card?

[Technoid1]

I want a PC with an Intel Core 2 Duo 1.8 GHz or better processor, 2 or more GB RAM, and Windows 7/8 (Preferably 7). I just need some sort of graphics card that supports openGL 3.0. I don't need EXACTLY that, it's just the minimum. My budget is around $100, so anything better that I can afford will work too.

I'm searching on eBay, and I don't know much graphics cards, but I read somewhere that the Radeon 7850 and Nvidia 650 ti supported openGL 3.0, and that someone's 7850 worked on a very low wattage power supply, so I was thinking about getting a PC on eBay, and if it doesn't already have one, installing a 7850, so that I won't have to get a new PSU too. Feel free to recommend something else (Better or cheaper) that supports openGL 3.0.


I found a few PCs start with, will a 7850 fit/work in any of these?

http://www.ebay.com/itm/161552250682

http://www.ebay.com/itm/281677825851

http://www.ebay.com/itm/391170799410

http://www.ebay.com/itm/201372649449

http://www.ebay.com/itm/371344658706

http://www.ebay.com/itm/231478720775

 

[James Junior]

Well half of the items you listed are already sold out and the only thing that may work is the Dell Optiplex MT 755