I vacuumed air intake; no change or improvement in SpeedFan over-temp readout. https://www.donation....msg434398#msg434398
In that post I try to explain why you see such fluctuating temperature values.
Usually there is a model number on the bottom of the laptop. Chances are that there are more than one video showing you how to dismantle your laptop model. In my experience, HP is adequate in delivering manuals for their laptops. Manuals that include all the steps to dismantle your laptop. Reverse these steps in the order as described in their manual and you should be up and running again without issues.
Depending on the model of laptop, it can be the case that you need to remove the whole cover before you are able to upgrade RAM or hard disk. if so, you are in luck. The manufacturer designed it so that it should be relatively easy to remove the whole cover and you'll have the benefit of easy internal cleaning without voiding warranty. If you have a model laptop where RAM, hard disk etc., each have their own separate small cover plate, then internal cleaning is more of a hassle. Just look at the bottom of your laptop and you'll see it right away.
As I understand, your laptop is from HP, they are more often than not designed to be serviceable. Except for their low-end consumer models. If you have a business model laptop (from any brand), serviceability is always better than for their consumer model laptops. In general, if you are in the market for a laptop, get a business model. Sure, they might not look as "flashy" as a consumer model, and likely have a slightly higher purchase price, but when it comes to maintenance and (tech-)support, you will be much better off in the long run.