Power supply is important, if you don't know how to find it put a picture of the label here or maybe if your computer is prebuild you can put the model number here. 520 is a slow card and there is definetely a lot of better options. I don't know what you mean by the 'CPU cabinet', explain to me what you really mean, I'm guessing that's the cabinet/chassis, but since you say 'CPU' I am not sure.
So information left is: What is CPU cabinet and was that the issue? and your Power supply.