On a working computer if you are able to go here:
https://www.microsoft.com/en-gb/software-download/windows10
Click on the
Download tool now which is approximately 5.5 MB
Once downloaded, run the tool which will then allow you to download Windows 10 ISO image. You need to select the same Edition, Language and architecture type (i.e. whether your computer is 32 or 64-bit) to match what you currently have installed on your computer.
Once its downloaded, the last screen has a couple of buttons at top left to allow you to burn the iso image to a DVD or to a usb stick. When the burning is complete on that same screen you click the Finish button.
You can now insert the DVD or USB stick into your other computer and boot from it to attempt to repair your computer or if needed to reinstall windows 10 over the top of itself (in-place upgrade). If you take that route there is an option to save files and settings you all ready have. During this process it ought to reinstall the universal apps including Windows Store.
If you go to the articles section of this Forum Ian placed an article there about using an iso image and how to get it etcetera which has pictures of the screens you see as its running.