Question PC will not go into BIOS and many other problems

Mar 23, 2020
First off, I'd like to say that this happened right after I tried to overclock my CPU.

Whenever I try to boot my PC into the BIOS now, it just freezes on the boot screen and does not load, I need to turn off the PC at the back of it in order to restart it. I have tried to reset the BIOS by removing the battery and then putting it back in, which worked for 1 try so my CPU would go back to it's stock settings. However, after that 1 time it let me into the BIOS, it hasn't let me in since.

There is also another problem which makes me believe it might be the motherboard. The 2 monitors that I have plugged into the internal graphics do not play fullscreen video at all anymore. They used to, before I messed something up, but now they don't.
(Also should be noted that I recently bought myself an AMD Sapphire Pulse 5700XT to replace an Nvidia 1050ti and idk if drivers have messed with it or not.)
All of my graphics drivers are up to date as well, including the internal graphics.

Specs of my PC because that may help:
GPU: AMD Sapphire Pulse 5700XT
CPU: Intel Core i7-7700K (reset back to stock clock (4.2GHz) after an unstable 5GHz overclock which messed everything up, it worked fine at 4.8GHz)
Cooling: Corsair H100i V2
RAM: G.SKILL Trident Z RGB 16GB DDR4 3000Mhz
Motherboard: Gigabyte Z270X Designare
PSU: Corsair CS650M (650W)

Any help given would be much appreciated.