Question Random grey screens

[Hijackeddd]

I recently bought myself an rx 580 but had to use it in my i3 4150 rig.Ive been getting random grey screens since.I was worried that it was a gpu problem but when i monitor usage the gpu usage is at around 20% 50c and the cpu usage sits still at 100% 78c.So i guessing that this is because of my cpu overheating,or is it?
Another point to note-my keyboard also stops working at this point.The mouse only lights up

 

[Archaic59]

Your system, aside from applications that focus on 1 or 2 cores, is very unbalanced but you already know that from the usage figures you listed. So, what is the brand, model and age of your power supply?

 

[Hijackeddd]

Corsair GS700 bronze rated about 2yrs old