It was a stationary screen - sort of like missle command - but there weren't really any graphics. The background was all black (if I remember correctly). There were two spots on opposite ends of the screen where two players could launch missles (they weren't actually missles, just an arcing line) at eachother. It was turn based and each player was supposed to enter a few numbers to aim where the shot would go. Each shot responded to gravity and, depending on the numbers you put in, would eventually arc back down toward the ground (and your opponent). Your shots could go off screen and come back on the other side.
Well, sounds like an archaic Gorillas!. You can get the game from QBasic.com and chances are you have QBasic somewhere on your computer. There are many clones of that game floating around, with the same gameplay and better graphics.
Yeah, there's SO many options, it'll be easy to find a clone. However, if you want the SPECIFIC game, you're going to have a hard time, it'll be almost impossible.