I recently bought a custom made PC and have only been using it for a good four days and it has run smoothly until now, after I did a windows update games are very laggy and will have black squares appearing on the screen. I have an integrated AMD Radeon HD 8370D graphics card installed on it and I can't seem the nail down the source of the issue, I'm not much of a PC expert so the voice of experience would be very helpful and appreciated.