I think Im looking for the same game.
As I recall it the game ran in a not so big window. You saw a top view of the solarsystem with the positions of the planets. You also saw the ships and their courses.
The fun part in that was that the planetairy orbits affected the time the ships took to get to the other planet.
Also, you could send a number of ships to a certain system, more planets meant more minerals.
The goal was to eradicate the other player(s).
It was a turn-based concept, in your turn you could send out ships, build new ones, send ships to other planets you owned, etcetera etcetera..
I hope someone can help find the game!
EDIT: I have found it, the game I was searching for is called Solar Wars.
I was wrong in the window size, it needs to be at least 1024x768.
Linky:
Solar Wars