Okay so I have an HP 620 laptop and it has ran fine ever since I got it, recently it had started freezing with no changes in fan speed or anything it just locks up and requires a restart which it then will freeze while starting windows and I have to leave it for a few hours or start it in safe mode, safe mode with networking works fine too but I have switched to a different HDD and it still did it, I did a memory test and nothing is wrong with my RAM. I've tried Linux and reinstalling windows and it still froze, I looked at linux's hardware monitor thing and CPU 1 would go down to 0% and CPU 2 would go to 100% and then they would change two or three times and then lock up when CPU 2 is stuck on 100%, I don't know how to replace a CPU in a laptop and I want to know if there is a fix for this or if anyone else has it. I run a server on my laptop so I don't want to stay in safe mode all the time.