I'm thinking if I can restore UNA, have access to the USB ports, then download XIA to a flash drive, then do the clean install, that would be painful but probably the best solution.
Access the usb ports......(tick)
download xia to a flash drive....NO...it is not a simple download to the usb stick/flash drive
First download the .iso file from
HERE ....then use
Balena etcher to "add" the .iso to your flash drive/usb stick......It is added via balena etcher that it amkle the usb stick BOOTABLE (Hugely important)
.....Balena etcher is downloaded to your pc. Then you Select the Image (the .iso file) ....select the drive (this will be your USB stick) ...then click on Flash .....this will burn (or add) the .iso file to the usb stick and it will be
bootable
When that has finished (it takes just a few minutes) ....you shutdown the pc...then plug the usb stick in .....hit the start button, and then start tapping the F7 key.
The boot menu will appear.....use the arrow keys to select the usb stick....hit enter......and then wait as the magic happens and the LIVE version of LM22.1 appears on your screen.
LIVE version....this runs in RAM....IT IS NOT A FINAL INSTALL.
Play with it for a while....you are looking to make sure interner is working, and sound, and all the stuff that normally works for you.
When you are quite satisfied, there is an icon on the desktop, that says "Install Linux Mint"
Double click on that, and the install process will start. From beginning to end it takes around 20 minutes...maybe a bit less.
You will see a screen like the below....
Note....that will erase anything and everything that drive. BE SURE you have saved anything that you want from there BEFORE you boot to the usb stick.
You will also be asked if you wish to install multimedia codecs....tick Yes.
The below link are the installation instructions from the LM site.
linuxmint-installation-guide.readthedocs.io
Have a read. Questions?....just ask here.