so i installed my new mother board, cpu and cooler a week ago. fresh install of windows 8.1 so that's going well. put some stuff back on such as skype, steam, four games so far, league of legends, spotify shit like that. was working very well, and still is. the only problem i new face is sometimes when running SOME games, my computer will run it fine for a while, and then for no reason will start locking up my whole computer. not just the game, but the whole computer. the two games this has happened with were reflex, and rocket league. with rocket league it happens more frequently. i'll be able to play a match or two, and then it will start freezing, and i've found out how to get it to unfreeze is to control alt delete, open the task manager and then just get back on the game and it's fine. but what has just happened to me three times today, is my whole computer will completely lock up, can't move my mouse, my friend can't hear me on skype, can't control alt delete or anything. i have to hold the power button to shut down my computer. i downloaded a cpu thermometer to see if my CPU was over heating or anything but it's staying at around 40 - 50 celcius which i'm assuming is target temperature. i don't think that would be the problem though as i'm able to run league of legends and counter strike fine which i would assume would use more cpu power than a game such as rocket league.
cpu - i7 4790k
cooler - cooler master 212 evo
mother board - gigabyte GA-Z97X-Gaming 3
cpu - i7 4790k
cooler - cooler master 212 evo
mother board - gigabyte GA-Z97X-Gaming 3