Written on the Power Supply itself will be 12v, along with 3.3v and 5v. The 12v will have under it a certain amount of amps. Most new power supplies have two or more 12v rails, added up should be at least 28amps. http://www.newegg.com/Product/Product.aspx?Item=N82E16817371004 For example (I'm not saying to get it). Under specifications it says: +12V1@18A,+12V2@18A. This adds up to 36 amps. Check specifications for when you're browsing power supplies and check the 12v, and again I recommend a minimum of 28 amps.

Look at the actual power supply. The amount watts is important, but especially look at how many amps it says you have for your 12v. If you have at least 370 watts and 18amps on the 12v that's probably the bare minimum. If not, you need to buy a new power supply to be safe. Get at least 430 watts and at least 28amps on the combined 12v rails, so that you're comfortably above the minimum (you never want to be at the absolute minimum if possible)

merynsid your processor and ram is enough... but that built-in-graphics will not do at all. Upgrade to a good PCI-e card, and when you do make sure you disable the built in one. http://www.newegg.com/Product/ProductList.aspx?Submit=ENE&N=2010380048%20106792462&bop=And&Order=PRICE Any of those will run the game fine, though I recommend getting a 512mb version.