The correct answer is: B. Keep the computer cover closed.
The computer cover is designed to keep dust and other particles out of the computer, which can help to prevent overheating. Removing the cover can allow these particles to build up, which can block the airflow and cause the computer to overheat.
The CPU fan is also important for keeping the computer cool. It helps to circulate air around the CPU and remove heat from the system. Removing the CPU fan can cause the CPU to overheat, which can damage the computer.
Option A is incorrect because removing the slot cover can allow dust and other particles to build up inside the computer, which can cause overheating.
Option C is incorrect because removing the CPU fan can cause the CPU to overheat, which can damage the computer.
Option D is incorrect because removing the slot cover and the CPU fan can both cause the computer to overheat.
Option E is incorrect because keeping the computer cover closed and the CPU fan installed are both important for preventing overheating.