how to reset computer without installation software

[KF-2020]

drive is 80% full so I would like to reset computer to original .  I don't have any installation software.  HP recovery assistant says I would need to have office 365 installation disk, which it says will be removed in recovery.

I have run all the disk clean and HP assistant maintenance tools but drive is still mostly full, so I would like to reset computer back to factory .  but I don't want to give up the office 365 that it came with.

I would also like to upgrade to windows 10 but I don't have enough space on disk.  I have deleted all the apps and programs, photos and everything I can find, but disk remains full.  I need something that will put disk back to original capacity.

thanks

[Lil_Boy_Blue]

Hi

The first thing I would do is to use Belarc Advisor and print out all the current settings and LICENCE KEYS.

You could probably make a backup onto a large USB stick.

https://www.microsoft.com/en-us/software-download/windows8iso

https://www.microsoft.com/en-us/software-download/windows10

Won't do a Factory Fresh, that is an F11 operation which will WIPE everything.

But I cannot help with obtaining the original Office 365 disk.

if in doubt please ask.