Hi Joutomies,
Welcome to the HP Community, I hope you enjoy your experience! To help you get the most out of the HP Forums I would like to direct your attention to the HP Forums Guide First Time Here? Learn How to Post and More.
I see that you are experiencing some overheating issues. I have included a HP document on overheating below to help you. Part of the problem is going to be because you are using an operating system that your model wasn't designed for. Some of the drivers may not be working properly causing the high temperature and the fan to run.
Reducing Heat to Inside the PC to Prevent Overheating
Thank you,