Weird issue: Every OS installation fails on this PC!

Hey there!
I've got an i3 build I put together myself. It was running fine on Windows 10 for a while, but then things went sideways—Google Chrome wouldn't close unless I forced it through Activity Monitor, even though Opera worked just fine in VPN mode. On top of that, AutoCAD kept crashing every time I tried to open a specific file. I tried a fresh install of Windows 10 by formatting the system drive, but now I'm stuck—the desktop shows the Start menu and taskbar shortcuts, but the actual taskbar is missing. I can see little preview windows when I hover over active apps, but I can't maximize anything or even resize windows properly. I tried installing Windows 7 Pro, but had the exact same issue. I even tried restoring a Windows 10 backup I made earlier with Acronis while everything was still working, but no luck. Windows 7 Ultimate actually boots, but it's a nightmare with driver issues—couldn't get anything installed, not even from the motherboard's original DVD. Even Hiren's Boot CD's mini Windows won't run.

Intel Core i3-6100, 3700 MHz, socket 1151
Gigabyte Z170-HD3P
Kingston 8 GB DDR4, 2666 MHz, HyperX Fury Black
Corsair VS650, 650 W

Two old hard drives
Hitachi and Seagate

I'm honestly not sure how to get this machine running again. Any help would be huge!

Thanks!

You might want to run CrystalDiskInfo just to see how that hard drive is holding up.

Thanks for the tip! I actually figured it out—turns out my PC was hooked up to the TV via HDMI, and the two displays were just fighting each other. I fixed everything in the settings using WIN + P.