I've been sharing this for over a decade and I'll share the link here but note we still don't learn Linux and we don't install Linux. We boot it, fish around with file manager just like in Windows and copy our files out.
BE SURE TO COPY!!! Once your files are safe, then you delete. If you MOVE files and the move fails you might lose files.
That's what I use when the OS does not work.
As to the save the OS, I find that when this happens about half the time I have to reload the OS or use the factory recovery which means all files on the drive are gone.
I have a Dell Legacy E7440, with some important files on it. Suddenly windows 8.1 stopped working, and it won t start anymore. It gives me a 0xc000021a problem, that, by reading on the internet, seems very harmful.
I tried few solutions, and nothing worked. I m thinking of bringing the PC to a repairman, but first I would take all my files out from the SSD in the boot up menu if is possible, just to prevent any lose.
Anyone has an Idea how to do it and will it be possible to save the operating system on the PC or everything must be renewed?