How to convert an MP3 file to MIDI on Windows?
That is not possible because MIDI is not an audio file format. It's a description on how to create music. Think of a midi file as a sheet music for a piece of music, whereas an mp3 would be a recording of someone playing the piece. So in order to create a midi file from audio recordings, you'd need some kind of score recognition program, which - to my knowledge - doesn't exist. A quick google search brought up a website and some software claiming to do that, but I wouldn't trust any of them. You can try it if you really want to, but even if they work at all the results will most likely be terrible.

If you need a midi file for a given piece of music, try to find the original score / sheet music! It's quite easy to create a midi version if you have the sheets.