are you on a laptop or a desktop ?
what GPU and driver do you have ?
if its an Nvidia GPU have ya tried to disable the Nvidia game works settings , and just use other lower settings ?
have you opened a support ticket with Ubisoft Support ?
i did not build your pc nor install the game on it ..so i or anyone on here has any clue on what your issue may be until you include that info
see the trouble shooting tips section i posted on Steam ..some thing there may help .. depending on your vid card and drivers .. you may just have a bad driver installed
http://steamcommunity.com/app/298110...6486417358966/ it may help
or it could be a backround application thats at fault
or it could be a failing Power supply in your system ..
if your GPU is not getting enough power ..yea your system can crash.... i know that first hand ..as i had to replace mine a few months ago
looked normal ..never smoked ...but everything that pushed my ASUS GTX 960 card would crash ..replaced the PSU ..problem went away
also make sure you verify your game files with uplay or Steam ..where ever you bought the game from