And I can't check your cleaning work or know if you knew to replace the compound and test if the heatsinks "landed."
I did have an odd one last year and it was HDD related. Tests passed but it felt like the HDD was seeking around a lot (defrag is not recommended, long story) and as a test we cloned the HDD and the problem vanished. Since the drive was 50 bucks and any more testing would have tacked another 100 to the bill, that was that.
There are too many kernel power discussions so I'll not duplicate priors and share what I'd do next.
INSPIRON 17 r:
Intel® Core™ i7-4500U processor
Radeon HD 8870M - Intel® HD Graphics 4400
I have a problem with my laptop Dell Inspiron 17 r 5737, after 20/30 minutes, the computer shut down, and in the event log I see Kernel power 41 63. I cleaned all the laptop, thought it was overheated but nothing this isn't the problem.
I used Whocrashed and I can't see a recent dmp.