Hey, I think I have that game in some shareware disc around here...
I'll see if I can grab some screenshots later...
For now, I think the name is TrekWar or something like it.
At least it is close to that image of yours.
EDIT: I did further search and it's Wintrek 2.0
Here, take a look:
If not, then it could be an earlier version of Warpath.
I even have another guess: Space Empires, try giving a check on that too.
If none, sorry I couldn't help.