Thanks for the help. The MIDI file plays perfectly as I expected. I wanted to try the steps you suggested but the very first step requires Windows 7 or above and my laptop runs Windows Vista so I'm not sure that would give the right result.
I also have to add, this is the MIDI-USB device I bought:
https://www.amazon.de/gp/product/B01487ZA3C/r … 0?ie=UTF8&psc=1
Oddly enough, the minute I bought it, the negative reviews started to poor in! It was 4/5 stars before, with the Roland USB device actually receiving worse scores. Of course, I had to wait so long for the MIDI-to-Gameport cable to arrive, it's too late to return it. So yeah, It's possible it's just a dodgy USB device. Oddly enough the older reviews are very positive so I got the feeling they changed something which causes it to no longer work properly.
In the mean time, I decided to try my IBM Aptiva instead. Same problem there. I also tried my main rig to host the software but I had to use an USB extension cable and now the MIDI player won't receive any data (on my laptop, when I booted up SQ4, I saw tons of activity in the software).
Now, I got two female-to-female MIDI devices and I swapped them in case one was bad but had no difference. Now if the software can't be the cause and I did nothing wrong, it must be either the USB device or the gameport-to-MIDI cable. That gameport cable took 5 weeks to arrive so if I order another, it might take just as long so that's not a fast option. I might just buy the Roland USB device - not cheap but it seems the best way to test it. If it gives the same result, I can just return it and get my money back.
Retro game fanatic.
IBM PS1 386SX25 - 4MB
IBM Aptiva 486SX33 - 8MB - 2GB CF - SB16
IBM PC350 P233MMX - 64MB - 32GB SSD - AWE64 - Voodoo2
PIII600 - 320MB - 480GB SSD - SB Live! - GF4 Ti 4200
i5-2500k - 3GB - SB Audigy 2 - HD 4870