Stuck note in MIDI

I need a tutorial on how to fix midis that keep playing one note when the song restarts. For total noobs please (press this button, press that button).

Do you have a midi editor that you kind of know how to use, or should I recommend one?

I once managed to change an instrument in Anvil Studio, that's about it...

OK, I'll give instructions for Sekaiju then, just because I know it a little better.
http://openmidiproject.osdn.jp/Sekaiju_en.html

Uh, do you have an example I can work with? I thought there was one in JPCP but I can't find it...

For me this song has a repeating note in prboom-plus with the SDL midi player: http://www.mediafire.com/download/0hec2b1qm4luxo0/GMGEO2.MID

So I've started writing a tutorial on that kind of thing, but I'm finding it tricky to actually cover all the possible cases and how to fix them in a way that someone unfamiliar with midi will actually be able to follow. So I might take some time to get it done...

In the meantime here's a fix for that track. It's the kind of thing where it's actually a lot easier to fix it than to explain how to do it :/

http://www.mediafire.com/download/2j7f0lko7zckdn2/GMGEO2fix.MID

Is it the MIDI file itself that's the problem, or could it be a bug in a source port?

(I know I've had a similar issue with an older version of GZDoom)

It was the midi, in this case the sustain pedal was not turned off.

What was the GZDoom bug? If it was with Doom 2's music in MAP14 & MAP22, that's actually a problem with the midi file too, a stuck note, but vanilla Doom turns it off when the song loops anyhow.