Windows PE (Windows Preinstallation Environment) is a software that one copy to CD or USB and boot it as live, Windows based operating system.
Windows PE is used to troubleshoot issues with Windows (reset password, fix HDD issue, backup/recover data, etc.).

Which Windows PE do you recommend?

I found following ones and it looks quite good, though i have not tested it:

Gandalf"s Windows 10 PE: http://windowsmatters.com/category/windows-pes/
Lazesoft Recovery Suite: http://www.lazesoft.com/lazesoft-recovery-suite-free.html
AOMEI PE Builder: https://www.aomeitech.com/pe-builder.html (this may be just builder, not pre-built Windows bootable solution)