You can always use a linux from usb to copy your important files first.
Bascially you install put linux on a usb. Put the usb into computer. Get your BIOS to boot from the linux usb stick. Don't install the linux, just run it of the usb stick. From linux copy all your important files onto another drive. Then go repair windows.
Lots of guides on how to do it if you google it.
for example this guy uses an ubuntu cd to recover files:
https://www.youtube.com/watch?v=AvsJ6OtSgTY