Could you walk me through the process in Windows to repair the MXF files?
In a word, nope. I don’t know the first thing about Windows. Someone else did it and gave the files to me, I have no idea what they did or how they did it.
I suggest just finding someone who is familiar enough with Windows OS and asking them to help you with repairing files or restoring or whatever. I think he might have said he used the MSDOS shell to do this but I have no idea for sure. Sorry, but from here I can be of no help.