Is it Joy?
Can you offer any other info?
Was it a hit? Was it happy or sad or mysterious? Was it fast, slow or mid-tempo? Was it in any particular genre? Disco, rock, pop, light jazz, easy listening?
I think so. Or a frequently played single.
Makes me happy.
Mid-tempo, closer to slow than fast.
I tend to think of it as both pop and easy listening.
Not an instrumental, but my guess is Cool Cool Summer by Bananarama
“No Matter What Shape Your Stomach’s In”?:
Well, I found this list from “Ask Billboard” Instrumentals, part 2 you might wish to peruse, seems like you might find what you’re looking for in there somewhere. I’m not about to listen to all of them and try to guess which is what you’re looking for without a lot more information to go on.
I’d be shocked if you, or anybody went through all of them. I’m going to try something that might make it easier to figure out. I’ll post back later on it.
It’s not Chariots of Fire, is it?
Nope, sure isn’t.
OK, not that this might be much help, but I tapped out part of the instrumental. If any of you have 16 seconds to spare take a listen. If that doesn’t help then don’t worry about it.
Keep in mind that the part I’m tapping out is done with a synthesizer/keyboard in the song.
Rise, by Herb Alpert?
Morning Dance, by Spiro Gyra?
OK, I’ll take one stab at it. There are a zillion versions of this out there, the original is over 10 minutes long. Can’t find the radio edit on YouTube. “Moments of Love” by Art of Noise. Here’s a 7-something-minute remix with footage that shows the xylophone live, along with all the other instruments that were synthed.
Jeez man, this is not that helpful. 
Can you hum the melody or something?
If you’re going through that trouble, can’t you at least hum it for us?
Anyhow, you can try tapping it with http://www.songtapper.com and see if comes up with anything. I tried the first two or three bars and couldn’t find a hit that was relevant.
I tried humming and felt embarrassed with the results.
OK, I have some things I need to do, but I’ll try humming it later and posting the update for you.
the 16 seconds of tapping reminded me of that terrible S-A-T-U-R-D-A-Y thing by the Bay City Rollers, which of course is (a) not an instrumental and (b) too shitty for anyone to want to remember.
Alan Tew, The Fence.
Your welcome 
It took me a lot of effort not to burst out in laughter and bother the guy sitting next to me when I read this.
Have you got Shazam on your iPhone… Phone… hone… one… ne… e?
Yo man in a 20 year old Dj from uab and I remember this song from my childhood I fell in love with it from the first time I heard it but if you haven’t found it yet I almost positive it is Paul hardcastle rain forest!!! Let me know I actually made an account just to reply I was look for the song for like 2 weeks and I saw this forum and did some extreme reasearch and I found the artist and felt like he sounded similar so YouTube and Pandora helped!
A swinging safari?