Some issues with Acer VN7-591G, and downgrading to W7.

Hey there.

First off, let me say I am not exactly an expert on hardware and software stuff, so please have patience with me. And I apologize for any grammar mistakes or typos. English is not my first language.

What I currently have:
ACER Aspire V15 Nitro Black Edition (VN7-591G-71Y3)
Intel Core i7 4720HQ Haswell
12GB RAM DDR3L
GeForce GTX 860M (4GB) + Intel HD 4600
120GB SDD + 1TB HDD 5400

I've been having this laptop for almost a year now. So far, it's great. Great performance, doesn't get too much hot, the booting is super quick etc. It also came preinstalled with Windows 8. I think like 4 months ago I took advantage of the free Windows 10 upgrade, which is when some of the issues started.

Basically 80% of my pre 2008 games don't work anymore and compatibility mode doesn't help either. Plus my Integrated Intel card (that's taking care of resolution etc.) now refuses to properly scale non-widescreen games on the entire screen (I get black bars on each side of the screen), no matter what I try to set up in the Intel HD Graphics panel. Something which seems to be happening only on W10 due to faulty drivers, according to some of the topics I've found over at the Intel forums. (and apparently hasn't been fixed for a year now)

The problem is with games like Hidden & Dangerous 2, Mafia, Chameleon, Fallout Tactics, Baldur's Gate series, Icewind Dale series etc.

I thought I'd solve this problem easy enough by downgrading my Windows to 7, but I've read up on it a bit and appears that it's not as simple as I originally thought?

1. I've read that I have to tinker with BIOS and switch it to a "legacy" mode, in order to have the old "installing Windows 7 from dvd" thing work and that it's somehow tied to the fact that it's a 120GB SSD + 1TB HDD hybrid. And that I even have to do something with Disc Partitions (?). I literally have no idea what this all is about, and I am afraid that I would mess my laptop up if I did something incorrectly, so does anyone have some step-by-step for dummies?

2. I've looked up the drivers for this laptop for Windows 7 and there doesn't seem to be any officials ones? Only for Windows 8.
I did find some site called Driverscape with drivers that apparently has them even for W7 for my laptop, but the site looks kinda dodgy.

Does anynoe know how to solve this driver issue?( In case I manage to get past point one, that is. ) I've seen plenty of people on the forums around the internet talking about how "they've downgraded to W7 on V15 or similiar laptop" with little to no details, so I am guessing it's possible somehow??

Also some kinda unrelated problems:

1. I have most of my games and music on the 1TB HDD. Sometimes when playing games (Witcher 3, New Vegas) the game hangs for like 1,5 seconds and the HDD sounds like it's just been woken up and is trying to keep up? I have checked in my battery settings if the HDD is supposed to go to sleep when idle, but this feature is already turned off. What else could be slowing down my HDD like that?

2. Crippling low wifi signal. I'm using the Intel (R) Dual Band Wireless-AC 7265 and for some reason it's really, really slow. My downloading and browsing speed is cut in half, unless I bring the laptop closer to the room with router. Then it's fast again. I've googled around a bit and this particular model I have seems to have some wifi problems for others too. I don't want to jump to conclusions though, so I thought I'd ask here as well.

Whew. That's about it. Sorry about the lenghty post.

And thank you in advance!