You posted that you had unplugged the UPS in order to kill all voltage to the computer. You need to ask yourself "what does a UPS do when the line voltage drops", the obvious answer is the UPS provides the line voltage. You need to unplug the computer from the UPS!
If you have all of your important data saved to removable media (external hdd, flash drive, DVDs, etc.) you could use Windows 10 installation media to run a Reset which will basically reinstall the operating system. This has the option of saving you personal data, the down side is that it will uninstall any third party programs you installed.
Booting from the installation media means that your installation of Windows 10 will not be used to make repairs, the recovery options include the Startup Repair.
How to perform a Windows 10 Refresh from Installation Media
A Refresh will basically reinstall Windows 10. This will not effect your personal files, but it will uninstall any third party programs you installed. You will be offered a list of the programs which will be uninstalled, you can use this list as a reference to these programs.
To do a Refresh on a computer which can not boot you will need Windosw 10 Installation Media.
If you don't have installation media you can use the Windows 10 Media Creation Tool to create installation media for either a disc or flash drive. Follow the instruction for the second option Using the tool to create installation media (USB flash drive, DVD, or ISO file) to install Windows 10 on a different PC.
In order to use either form of installation media you need to change the boot order in the BIOS so that the type of media (disc or USB flash drive) is the first device in the boot order, and the ssd/hdd the second device.
If you are using a disc place it in the tray of your optical drive, close the door and restart the computer. When the computer recognizes the disc it will instruct you to press any button to boot from the disc.
If you are using a USB flash drive place it in a USB port and restart the computer. You will receive the message to press any key to boot from the device.
There is a very good tutorial available, you will find it here.