Let me just say that the Reset function in Windows 10 (either with keeping personal data or a complete reset without keeping your data) will not work. You must download a new copy from the web.
I have a theory as to why it happened to me. On the Windows menu the menu item for the Microsoft Solitaire Collection is next to the Windows Store. If a person intends to delete the Solitaire Collection by right clicking/uninstall, and instead right clicks the Windows Store/uninstall by mistake it will delete the Windows Store.
If it is too involved to fix the bug at least Microsoft should put a popup if you are about to delete the Windows Store warning of the consequences of deleting the Windows Store.