I would suggest you Windows 8.1 x64 as running OS. It runs very stable over here since weeks now, and most likely every game is running over here.
After installing Windows 8.1 don't forget to install Microsoft Visuals, JRE (Java Runtime Environment) 7 not 8 - JRE 8 update 20 and newer have serious errors with running Java = http://www.oracle.com/technetwork/java/j...32155.html
I'm not sure when the windows 8 internet defense force showed up, but it's 'weeks of reliabilty' for an OS that's been out over a year (two years?) vs windows 7 that's reliable from the moment you install it, and no conflicts with software or hardware. I had to spend hours trying to remove windows 8 from my brothers laptop because it simply destroyed everything and had conflicts with every damn thing on it.
Don't even consider it, it's not worth the heartache.