Operating System - New Laptop

Leaning towards windows 7

You'll have to pirate windows 7 as its no longer supported by Microsoft.

Windows 10 is the OS popularity favourite. Just about any place sells a license. https://www.amazon.ca/Microsoft-Windows ... 186&sr=8-5

Ubuntu if you want to do alternative to Windows.

Windows 7 also does not have support for Intel CPUs that are Kaby Lake and newer. That's 7th-generation Core CPUs. I'm sure you won't be buying a new notebook with a CPU that is over a few generations old. Your choices are only Windows 10 or some flavour of Linux.

If there's no Windows key sticker, the licence is probably embedded in the BIOS, in which case, you can download a Windows 8/10 ISO and it will pull the licence from the BIOS.

Personally, I use the HeiDoc tool to grab ISOs from a Microsoft site, but there are other methods:
https://www.heidoc.net/joomla/technolog ... nload-tool

You may also have downgrade privileges with the machine's licence, but not sure.

As a Linux fan, I always boot a 'live' version of my favorite distro (LMDE) on computers that I have access to, in order to check compatibility -- and, if working well, proceed to an install. More recently, if the firmware is newer (UEFI), I would also consider dual-boot installs with the 'Brunch' version of ChromeOS. I even have one machine where I triple-boot with the already-installed Windows 10.