This is a long shot, but here goes anyway:

Do you, by any chance, remember an old Commodore 64 game where you're playing some treasure hunter...I think you're in some caves collecting diamonds. What I do remeber for sure is the fact that you can disappear and then reappear in a different place. It was a very fun game, which I used to play a lot with my kid brother. It's kind of nostalgic to me, and I just wish I knew the name.

Oh and I also remember the music, I can recognize the game just based on that:

"tu du du du du, tu dududu dududu"
(well that line means absolutely nothing unless you hear it, but if you already think you know which game, then that line might help)

...that is, if you even played games back then, and if you even remember anything. Like I said, very long shot, but I had to try.