Just perform a Windows Search for *.myi files on your local partitions. Period.
As I suspectected, they were located inside a program files folder, instead of using a proper data-only folder like most other database managers do.
Why do a my.ini file search, open it with an editor, look-up the path string, make sure you don't alter the config file (!), and then do a second search? Complicated without a shred of added benefit other than to practice touch typing.