That laptop locked me out because it didn't like my typing in my password and the poor quality 'security' settings I had no control over. So it now has linux on it.
Well, you can copy files off, and then remove the old os via deleting the partition and then putting it back. Then you can install whatever you want on it that is compatible with the hardware.
booted recently with krd18 (https://support.kaspersky.com/viruses/krd18) and saw it has windows password reset option. i think this will help. same possibility, if i remember correctly, is available in distro parted magic (it's not free, but its free version runs from Ultimate boot cd https://www.ultimatebootcd.com/) yes, you are right, windows are not so tenacious as to prevent new installations when it have already been removed. perhaps didn't get enough sleep
If you're paranoid, you can also run some stuff in a virtual machine, or on a system booting from USB drive. You can look at alternate browsers too with security plugins. I use TOR as a main browser for lots of things, PaleMoon as alternate (it's a FireFox fork with access to a lot of FF plugins tailored for it too, like no-script, adblock latitude or a cookies exterminator... and my beloved FoxClocks for easy time-zones reading) and an up-to-date Firefox for a very few things (like EQ2 forums). Brave is very good with security built in but sadly it lacked the easy language switch I need last time I looked (I need to be able to switch language dictionary from english to french and the reverse without restarting my browser)
