Hello... WOW good testing and analysis B )... 4) What was the Orig OS ?
Original OS delivered was Win 8.1. I upgraded to Win 10 last summer when I got tired of saying no to MS.
OK you have found what I have learned about OS's, drivers and hardware. "Only certain combinations work" I'm using a 3 year old NVidia driver... why? cause it works " if it ain't broken... don't try to fix it." B )
In reality, we've pretty much lost control of the platforms starting with Win7. Suppose it started with the Apple IOS mindset and its proponents. There is so much going on under the hood with auto updates that it is inevitable there will be incompatibilities. The hope is that between MS and major HW manufactureres it is sorted out in a timely manner.
Typically the machine, Chips used, and Hardware was created/designed/and TESTED under the Specs the product will be marketed as... and if you use the SAME OS, hardware, and SAME drivers that came with that machine... it will work as advertised.
IF You are trying to "deviate" from the Specs... to the Company, your 2 year old machine is a 3-4 year completed Engineering project... There is no more $$$ or time available for it... they are off building the next Great? thing. No one there is worried about your free WIN10 drivers or hardware, NO one IS working on it... or taking responsibility if the latest intel driver doesn't work... the next programmer could have deleted that Line of Code. LOL... They just want you too BUY a new one if your having problems.
Why I'm reluctant to put any big $$ into any repair. The Asus CSR rep was professional and tried to be helpful but took the attitude that it is a HW problem that needs repair (there is an annoying flickering if the display lid isn't in a good postion, indicative of either wear in the wiring harness connecting from the laptop body to the lid or perhaps the switch embedded in the hinge). Everything that I see is this is strictly a SW, drivers, OS incompatibility issue. I was hoping someone would know about it and say...find this registry key and change to this....that's what it seems like to me. That is probably too simplistic. The level of integration between hardware/firmware/software in laptops/tablet is the enabling technology but also it's Achilles Heel. It all has to work together.
You have found a operational problem... but was the problem caused by the owner? changing the OS and drivers from the factory fresh ones? Get the machine working as shipped and Will that be Good enough for your Use?
5) Yes... ASUS will have ALL Orig drivers available... either online or they can send you a CD... I suggest you copy them and keep them in a safe place.... up to 5 years I think is the US law for consumer protection for replacement parts?
I'm wondering if the real solution is to get a copy of Win 7 and give that a go.... I have a 5 year old Gateway laptop running Win 7 Home that is still solid, though slow and beatup. Win 8 was a disaster and Win 10 is quickly becoming just another MS patchwork of fixes. Of course, that assumes that I can get drivers that are backward compatible to Win 7.