Question games not running on a good system

[EKI002]

I'm having problems with my computer not running games i should be capable of running
some examples being. just cause 3, sleeping dogs, Raft and many more games
my computer specs:

rx vega 56 8gb

intel i7 6700

corsair vengeance ddr4 8gb x 2 ram

750W power supply

1 terabyte ssd

b250 msi gaming motherboard

if you are able to help with my problem pleases reply to this post.

 

[rgd1101]

what exact do you mean not running?
brand and model of this 750w psu?
did you upgrade the system without reinstall the os?

where the game from?