So I have a stock Hp computer, the model number is an HPE-515t. It comes with a 300 watt power supply and I am wanting to upgrade to at least a 500 watt supply so as to upgrade my graphics card. Is this as simple as picking out a new power supply and hooking it up inside my tower or are there other considerations to take into account? Also any advice on the proper psu would be great, so far I'm looking at a corsair 600w.