I purchase my own physical Genuine Microsoft OEM Windows install disc and guard my Windows Product Key jealously. So much easier to install, reinstall, migrate, upgrade, clean, or repair the operating system when you have your own WinOS discs (or, quite often, copies and images of your own WinOS discs). Especially when you need to deploy across many machines (which can all work for month or three from one copy, you just invoice the owner for more cheap Windows Product Keys) or when you get stuck working on sick old machines running on decade-obsolete software, lol.

Basically if you plan to install and reinstall Windows operating systems on many machines for many years then buy yourself a real copy. You can even download (most) WinOS copies free from the Microsoft sites, though you will still need to own Windows Product Keys to properly use them. Yes, "Third-Party" and "Branded" OEM WinOS versions are always inferior - preloaded with "value-added" bundles of trialware and bloatware and junkware, with the core OS files always encrypted or butchered in some way to protect the licensed-OEM from liability caused by software piracy.

A completely fresh and clean full operating system install on a freshly-formatted drive is almost always better than any kind of "in situ" operating system upgrade, repair, or reinstall. Though you'll also need to install all of your hardware-specific drivers manually - and it's best to have them already downloaded and archived before you start so you're not obstructed by can't-boot-or-can't-go-online-without-the-driver-installed problems with your network or drive hardware. You'll also need to have your Windows Product Key and any other product or hardware keys written down, and some of these are hidden or encoded in ways which make them a pain to extract. Yes, you're a legit end-user running a legit copy, but Microsoft's built-in assumption is that nobody would ever circumvent their system unless they're a software pirate.

You may also want to save any of the little things ASUS has preinstalled on your laptop - ROG-themed wallpapers, icons, cursors, sounds - little ASUS hacks in the Registry - any bonus software or configuration tweaks which ASUS included but which aren't readily available from their download sites.

You may want to repartition your drive(s) before installing the operating system. You might lose the contents of your "recovery" partition or any hidden/protected partitions in the process. WinHex can "forensically" detect and read any data hidden anywhere on any drive, CloneZilla can clone and image anything you want to backup or restore.