My father purchased an ex-lease laptop from a trademe in-trade seller, which also came with a 3 month warranty. The computer all looks good. But one of the reasons they purchased it was because it came with Office 2019 Pro preinstalled and all activated, so there is no subscription required.  It all looks to be working fine, and I have updated it to windows 11. But I am wondering how the MS Office license now works, and what happens if I need to reinstall a clean version of  windows and Office at a later date. Do I just download it from MS and install it, and it reactivates again like windows does, where the license is tied to the PC? They don't have any office account themselves.  I am wondering if I should instead back a backup copy of the windows install, so I can restore it back to how it is now, if it ever needs to be reinstalled, and that would then restore office too.