I've been trying to remember but it hasn't come back to me. It was a 2D, top down, space battle game. Its possible it wasn't named after Star Trek, but you pilot a grey ship with a saucer section and nacelles to fire torpedoes and phasers at green bird of prey looking ships so...
That all sounds very familiar. The one I played was full color but it must have either been a late version of Empire or something heavily "inspired" by it.