Something that you might want to look into, though it's kind of a long way around the barn to get to the final goal, is to create a Ubuntu disk.
I've use mine twice in the last week on computers that wouldn't boot.
It would probably take you and hour or so to download and create one.
It's a handy thing to have around.
If you are pretty sure that replacing a specific folder will fix the problem it would work.
The disk has booted every computer I've tried it on and allowed me to access, copy and paste files to and from the computer.