Have you tried using a system restore, using a date before your system files were corrupted?
This will roll back all your programs to that date. Any files you have created or updated will still be there.
@Harrier
This was one of the early attempts, only to find out my system was set to use only 1% of my storage space to save restore points. Because of that it had only one, of about an hour before, which was too late by the time I was trying this.