well I managed to restore my previous installation which was nice, so I'm back to square 1
at least my PC isn't
that bad, so I can live with it for a bit longer, plus I've learned a whole bunch of useful tips that might help for next time. Bit annoyed but feeling better than yesterday, although my cold is full on now.
edit
looks like I've lost one of my harddrives. RIP.
fortunately nothing personal/important was on it, but plenty of stuff that I wanted, like references I've saved over the years, PDFs, some anime/manga, etc. So I'm trying all sorts of recovery but the drive is really being stubborn and keeps crashing stuff.
Fortunately the drive has 2 partitions, so I can do a test on the one that has less important stuff and see if it works. But I'm losing hope.
edit2
well after a huge amount of trying out stuff I basically found a sequence of actions that allows me to access the drive without it crashing. needless to say I'm copying everything to my spare 1TB drive before it dies completely. I think there's some sectors that I won't eb able to recover, but so far it's soooo much better than previously. Like all my art book PDFs and so on I'm recovering as we speak. soooo much happier than before, needless to say

....wait no it still crashes. so still a lot of work ahead. at least I've saved the most important files. if i try and access a sector that's busted the whole thing crashes, so I've got to be patient as well.