Windows license stored inside BIOS. When you install fresh Windows, it'll get activated automatically.
What's more troublesome is that some laptops require drivers and customizations, so you need to tinker with your fresh Windows by installing carefully selected subset of drivers, so your hardware works and at the same time you don't install the same shovelware. The driver situation for Windows is truly dire. There are drivers from laptop manufacturer (e.g. Lenovo). There are drivers from part manufacturer (e.g. Nvidia). There are drivers that Windows was bundled with. There are drivers that Windows will download automatically and install as part of Windows Update. It's a huge mess and I don't think anybody knows how to navigate that. So there's no reliable recipe to create "stable" Windows from the scratch.
> When you install fresh Windows, it'll get activated automatically.
Same happens with some crapware provided by vendor. You can wipe drive all you want, but ASUS motherboard will ask Windows to automatically install "essential drivers", and to be specific - "Armoury Crate".
You can (partially) blame Microsoft for that. I still don't understand why it's seemingly OK for device manufacturers to distribute such crapware through Windows update. New keyboard? Oops, spyware. Printer on your LAN? Here, let me install these 16 utilities for you. Just give me a driver without any GUI tools. Or at the very least prompt me before installation.
What's more troublesome is that some laptops require drivers and customizations, so you need to tinker with your fresh Windows by installing carefully selected subset of drivers, so your hardware works and at the same time you don't install the same shovelware. The driver situation for Windows is truly dire. There are drivers from laptop manufacturer (e.g. Lenovo). There are drivers from part manufacturer (e.g. Nvidia). There are drivers that Windows was bundled with. There are drivers that Windows will download automatically and install as part of Windows Update. It's a huge mess and I don't think anybody knows how to navigate that. So there's no reliable recipe to create "stable" Windows from the scratch.