If your computer’s recovery partition is damaged or missing:
Microsoft offers their Windows 10 recovery media via the Windows Media Creation Tool which can be downloaded from their website.
To download the Media Creation Tool, visit this link: http://go.microsoft.com/fwlink/?LinkId=691209
Run this tool on a working Windows computer. You will need a 16gb USB flash drive dedicated to this task. The Media creation tool will wipe this USB drive, so if anything is on it make sure to back it up first
Choose to create media for installing Windows on another computer. You’ll want to make one for Windows 10 64 bit (this should be the default). The download should take a while as it’s over 3GB in size.
Once the drive is created, you can remove it and plug it into your computer that needs to be repaired.
This process will remove all files and programs from the computer that is being repaired.
Power on that computer, and at the manufacturer logo press F2 repeatedly to get into the BIOS settings. In the menus there will be a selection for enabling the F12 boot menu. You want to make sure this is on. Save the changes and restart the computer. This time at the logo screen, repeatedly press F12 and you’ll see the boot menu. Choose to boot from your USB drive. The Windows 10 installation will begin.
When given the choice, choose to install Windows 10 (clean install), and choose advanced drive options. You’re going to see a list of partitions, click each partition and delete all of them, you’ll be left with one big single unallocated space. Press new to create a new partition. Windows will make a couple other partitions by itself, but one of them will be much larger than the rest (it’s usually at the bottom of the list), this is the one you’re going to install Windows on.
Go ahead and proceed with the installation. If this computer initially came with Windows 10 on it, the Operating System will activate automatically when you connect to the internet during the initial setup process.
I recommend hanging onto this USB drive in a safe place just in case you need to reinstall Windows again in the future.