Insert and tighten all the screws carefully. They are quite small, and the PCB may be damaged if the screws are over tightened.

Tighten the screws in an alternating pattern. E.G. Top left, Bottom right, Top right, Bottom left. With more than 4 screws, use a "Star" pattern when tightening the screws ensuring all screws are evenly tightened.

Clean off any noticeable dust on the GPU.