Specs: intel i7 4710HQ ~3.3 GHz
nvidia gtx 850M 4GB
16 gb ram

For starters this cant be a dust problem because it literally happened over night, and i know its the gpu because i used msi afterburner to check this. I dont know what happened but this is what i know: i have black ops 2 and i ran it at ultra specs at a smooth 60 fps with the GPU clocking at about 80/85%. One day it is like this, the next the GPU was at 99% use, which caused lag... This happened with all the games i hve in my pc: watch dogs, Mortal kombat, assassins creed rogue... Does anyone know what can be causing this?