hey! i dont know wats happening in my pc in gaming. when i was using win. 8 games like crysis 3 ,PES 2016 were running succesfully.but after upgrading to win.8.1 nfs 2012 and battlfield 3 are not loading.they are stuck on thier loading.wat should i do? go back to win 7 or 8? help me plzz..