I've been having some overheating issues lately. Initially it was only during gaming, but it's begun to overheat even during casual use. It started when I replaced the Intel stock cooler due to noise issues, but stopped after I moved to a case with more fans and better airflow. Now it has started happening again, and adding more fans and switching back to the stock cooler haven't helped. I've been monitoring the CPU temperature, and it hasn't gotten anywhere near the maximum. After overheating, it won't start up again until it's been unplugged for half an hour. The motherboard is a Gigabyte H55N-USB3, and the CPU is an Intel i3-540. Is there anything else I can do to prevent the overheating, and if not, what should I replace?