I no longer have the ID I used 5 years ago, is there a way I can access this file?
If that means that you can't remember the credentials in effect when that *.mny was created, then I have no solution for you.
If you remember, but changed your LiveID since then, then disconnect from the internet. Then try to open your *.mny file with the credentials in effect when that *.mny was created. Once in your file, remove the LiveID.