Dv6 i7 high rev fan shutdown, no high temperature

[Wiwa]

So i have a problem with this old hp envy dv6 i7 2670qm beats version. Bought it in 2011.
With 4gb ddr3 (originaly 8gb, but i broke 1 ram), 750gb hdd. ive done few repairs to it myself. it runs fine untill last week.

Though i have other tools i can do work with. I dont like the idea of throwing stuffs away, so im trying to fix this. Since it has been a great workhorse for the things i am doing. Many times i leave it over night to do some renderings, with no extra fan. Dv6 i7 2670qm radeon hd7400 is not the best build quality, plastics broke off easily. an oldtimer laptop, but still good enough for me, i7 2670qm is suitable for work, in my opinion.

The first problem was loud fan noise high temperature, then the thermal switch off kicks in, instant shutdown. I found the solution, So i open it up, clean the radiator from the dusty hairy stuffs thats been nesting inside it. also replaced the thermal paste. This is the third times ive done it since i first bought it. It collects dust rather easily i could say. this is the first thermal switch off, i think i forgot to clean it for quite a long time.

The problem was gone after i clean it (not entirely). The fan once again running smoothly between 850-1100rpm idle. The idle temperature is around 40-60c. For daily use,browsing, watching movies,lightroom etc works fine.i even test it idling overnight. It still works fine. Runs better than before.

But now it can no longer do heavy work. For example, everytime i use hitfilm 4 express and make a proxy for the video files. Everytime the fan revs higher for few seconds, thermal swithoff kicks in and it instantly shuts down. But no high heat was detected through the touch of hand, in fact its rather cold, normal.

What ive read from this forum the problem might be the bios, it need to be upgraded. But im not sure its possible (or is it possible) because, even when im doing hdd diagnostic it shuts down when the fan starts reving, luckily nothing bad happens. So everytime the fan revs high, the laptop shuts down with no heat threat or warning whatsoever.

im not a technician, just a diy guy. So i have a few question and a proposition :

1. Is the processor / mobo might be broken? Is it possible that the thermal switch off is broken or is it a software problem.
2. If i fail the bios update (because i belive it will shutdown in the middle of update) and it became a brick. will it somehow effect the hardware?
3. (Proposition) im still planning to use the i7 2670qm for longer time. am i better off salvaging the parts and cannibalize the parts to other compatible laptops with better build quality. Like the hp probook 4530s i3, hp elitebook 8560p i5 (any other suggestions?) That is rather cheap nowdays. And swap the i7 2670qm into it (ive read that its compatible), also i could use the old led panel from dv6 as backup part.

What is the best solution that you guys think is best for me?. I really dont like throwing stuffs away, i'd rather fix this and maybe give it to someone in need. because its a hard achievement for me to purchase this laptop back then.

Thanks,best regards.