Have this laptop's temperature sensors gone arwy and how to investigate?

A family member replaced an old laptop and let me take a crack at fixing it. Starting it up, the fan ran loudly and the computer ran incredibly slow, crawling through Windows startup. It is an HP Envy M7 I think about 10 years old, from the outside in great shape. Using a USB boot drive I reformatted and installed Linux Mint. It seems to run fine now, even streaming video, except the fan still runs loudly almost nonstop. There are times it briefly slows down only to fire back up again. That is, until tonight. I searched around to learn about system temperatures. From a couple of routes I saw v

Question by cr0 on Super User, licensed CC BY-SA. We show a short excerpt and link to the original thread as credit.