I was going to make the same move (Linux Mint).

I have 2 PCs, both running XP. One I use as an emergency back-up pc only, but internet-connected.

Where would you suggest backing the files up, and any particular ones, amongst the years of accumulated junk ?

I've also got Ubuntu on one of my three HDs on this pc...I think, to make it bootable, again in case of emergencies (so long ago put there, that I can't remember why I did so. lol).