A customer was presumably exercising the unlimited support part of their support contract when they asked, "Where is the full song for the music that plays when you start Windows 98 for the first time? The Welcome application plays only the first 30 seconds. Can you send us the rest of the song?"
I guess the IT department really likes that music and wants the extended dance remix for their late-night raves. (If you stick it out, there's a special appearance in the linked video of the screen I wrote.)
The music was commissioned to be 30 seconds long. There is no extended version of the song, or at least not one that Microsoft acquired the rights to. The original composer could have written a five-minute version and sent Microsoft only the first 30 seconds, or maybe the piece is only 30 seconds long to begin with. All we know is that we have a 30-second music clip.