I had the same problem over the summer,was running a HP setup was already 6 yrs old. I have a micro center right down the highway from me, so i bought a cooler master haf912 case,Asus z87-c mobo,intel i5 4670k processor,i installed a thermaltake 600w power supply,16 gigs of ram,i at the moment still have a nvidia gtx550ti vid card,i cant tell you what a relief it is to just turn the thing on and be able to play with no problems (other than my flying)!! all total i probably spent about 850-900.00 on build