Need help choosing

I just inherited a built PC from a friend who quit gaming after accidentally resetting his motherboard and corrupting something on his HDD. I have started looking into it and have found out that the current system is barely more powerful than my Macbook, significantly better, but by todays standards, its barely usable for bigger games. He almost exclusively used it to play League of Legends. At the moment it runs WoW, LoL, Morrowind, and Minecraft (All I can get on it atm) perfectly fine, but I want to take the thing to the next level.

I've done some research and as far as I can tell (and I'm going to need help with this) I know all the parts on this build and have looked into replacements. SO here are the current specs, If what I have is fine for now go ahead and let me know, my build knowledge goes all the way back to Late June 2016, so assume I know almost nothing lol.

MoBo- MSI Z77 MPOWER (I really want to replace this because of the limitations on the CPU, at least to my knowledge)
CPU- Intel i7 3770K quad-core 3.5Ghz (want to upgrade to a 6th gen i7 6700K, don't think I can with the current MoBo)
GPU- (least powerful component I think since he only wanted it for LoL) NVIDIA GeForce GTX 650 (also WTH is the difference between NVIDIA and EVGA ?!?!?!)
HDD- (had to replace this to use the rig so I'm using a cheap solo drive) Seagate 500G HDD
SSD- (not in atm) Haven't really looked at it well, all I know is it's around 250G
Case- Corsair, can't find the model, Full ATX Integrated cooling fans
THINGS I HAVE NOT LOOKED INTO
Power supply- no clue, it runs what I have
RAM- 8G, don't know what brand but I think it's only got one stick, according to my friend it can use up to 4

So its not a terrible rig but I have noticed its pretty outdated and it doesn't have the power to run the games I want to play on it. Mainly Fallout 4 and Skyrim-remastered when it comes out, definitely others when I can. But it is set up so that I can replace every part of it eventually and I plan to do that. Here is what I am thinking so far.

MoBo- Gigabyte GA-Z170X Gaming 7 (From what I hear this is a superior MoBo in my price range, only about $250, but has a few drawbacks, apparently the sound is not reliable and a lot of people are having problems with it, I'm not willing to spend much more than $200 on a MoBo since I will need to buy the $350 CPU along with it and about $600 is my budget for a single purchase and has to be good with overclocking)

MoBo wants: Black and Red or White and Red color, Z170 chipset, no more than $200, doesn't overheat bad when overclocked, entry-mid level build, LITTLE TO NO HASSLE.

CPU- Intel Core i7-6700K 4.2Ghz quad-core (I'm pretty set on the processor just need to find a good MoBo to put it in has to be easy to overclock)
GPU- GeForce GTX 1070 (can't quite afford the 1080 or I would, it's just a little more than I am willing to spend for not that much better performance)
HDD- Want to upgrade this to at least a 1T not sure which brand to go with though, I notice most people are going to primary SSD instead so I might do two 850 EVOs.
SDD- pretty set on a Samsung 850 EVO 500G or more
Case- (Case I have is beat up and broken or I would keep it) Corsair Graphite 780T Black and Red
RAM- uses DDR4 that's all I know, don't know exactly how many slots the MoBo has but I want no less than 32G RAM
Power- need to look into what I have, I most likely need to upgrade that as well.

This is what I think I want, I'm not sure if I am overlooking any other essential parts (like a sound card, I think it is integrated in the MoBo but I might be wrong)

So this will technically be my first build any advice or suggestions would be much appreciated. The price range I am looking at and am okay with is around $1500 and this rig is almost exactly that before taxes.

Thanks in advance!