How to create a Windows 10 bootable USB from installed Windows (not ISO)? [duplicate]

I have a laptop without CD/DVD came with Windows 10 installed. Windows can be re-installed from within the Windows, but what if I want to change my HDD or hardware failure or temporarily installing standalone linux (not dual boot)?

How can I create a bootable USB from which I can re-install my original Windows?

Note that I don't have an ISO file, just the original Windows installed on my laptop.

My question is simple, I just want to have an external backup to restore my Windows installation without relying on the main HDD.

You can use the MediaCreationTool to create an ISO of Windows 10 and get it on a DVD or create a bootable USB with the tool.

Windows has an embedded feature for that :

http://windows.microsoft.com/en-us/windows-10/create-a-recovery-drive

It will help you make a recovery USB that you can use in case you have an issue with your computer.

As you are running an OEM version on your PC, the recovery implemented by the manufacturer might have an option to backup it (on DVDs or USB). Check the documentation to get more infos.

This used to be possible in Win XP but I don't believe it is possible to build a clean install from an installed operating system.

You can create a System Image from Windows Backup and Restore and a recovery disk to launch the image restore. Before you do this you will want to shrink your partition to just larger than the space used on the HD. The image restore will only work if the image partition is smaller than the HD partition, even if it is unused space.

To shrink a volume, Right Click on 'This Computer'>Manage>Shrink Volume.