Regrets for the computer: best to have a small SSD for a safe operating system, Linux or Apple etc.; save to detachable hard drives and keep all non-operating files on them *; and rsync those file incrementally each day to other hard drives. --- or the Cloud if you trust that.
I do get sick of wise people wagging their fingers primly and going on about back-ups --- not everyone in the world can afford extra hard drives at any time.
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Linux and the BSDs of course separate the operating files and put all own on stuff into your own home folder: for instance mine is /root/home/falcon, Falcon being my middle name.
Anyway, do not despair of recovering the files: hold on to the disk(s).
When possible, attach it to a hard disk enclosure via usb, and see what can be recovered and moved off. After that I've had good luck in retrieving some files with PhotoRec and TestDisk: the first is for finding individual files and the second to fix lost partitions, both from the same firm.
They even work on Windows of all things, though one has to know how to type into a unixlike terminal.
And they are annoying, can dump files unnamed into a heap, but that's better than nothing. And not costing the thousands computer recovery firms can charge...
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EDIT: just remembered, decades ago when I used Windows, Runtime Recovery Software was very good. But I see it now costs USD$79 ( for life, though I long lost the email I bought it with... )