Hello! First off I’m fairly ignorant when it comes to computers, so bear with me:
I was playing in my 5 years old computer when a Windows (10) Update started downloading and slowing my computer down to unbearable levels (opening a folder could take up to 10 seconds when it would normally open smoothly in under a second). I decided to leave my computer downloading it all night and the next day I was required to reboot my computer in order to apply the update, upon doing that my computer entered in a forever rebooting cycle where it starts booting showing those BIOS options, then it proceeds to show the windows icon with those rotating balls implying it’s loading, and then it goes black and back to the BIOS settings, etc.
I’ve tried reseating RAM as it was pointed to me it could be the problem, after that the PC now sometimes completely powers down and up again, but only sometimes (I tried holding the power supply cable while it was booting and that seemed to make the whole powering down better) but it still goes into the infinite reboot cycle…
I’m sorry for not knowing exactly which details are important to point out, but I’ll gladly give you any system specs that I can, or any circumstances that might be relevant!
Welcome to the forum.
Some of us have used Windows for years and are having a hard time with Windows 10 updates. At this point, you can try to do a recovery. But they is a catch.
The catch is that you need to install DVD or some other method to repair the computer. From what you describe, it had gone beyond that point.
Do you have the DVD used to install Windows 10 ?
If so, boot it up and look for a place where it says you can repair your computer.
But if you do not have the DVD or USB stick used to install Windows 10, you hare going to find it more difficult. Iff you never see the “Advanced Startup Options” then you have to fin another way to do it.
You may have to ask a fiend to prepare a USB drive with the version of Windows 10 you have. The hard part is that it has now become near impossible for the average person to know what version of Windows 10 they have. Like it is maybe a top secret thing.
Does the computer documentation indicate what version you had? Does the maker of the computer know what you had? You should have in the documentation some way to call the support desk of the maker of the computer and find out it that can recommend a way to recovery Windows 10 on your computer.
Why did I not suggest you use another PC to download the ISO file from Microsoft.? Well, you have to know which version you had. Use the wrong version and things get worse.
Do you have a backup of the whole system? If so, you might have to use it now.
EDIT: Here is more about repair of Windows 10. 
https://www.laptopmag.com/articles/repair-windows-10