I'd take the hard disk and put it in a working system. THen I'd copy the contents.

You shouldn't need to fix the MBR to read the contents on the drive. The MBR just allows that drive to boot.

If it is not a bootable drive, there is no need to fix the MBR. YOu just need to hook the drive up and copy the contents as quickly as possible. It sounds like the drive is dying.