I remember this game also. In fact with an Atari emulator you can play it and other games on the PC just like you would on the Atari. You won't even know the difference. Only that since you are using the monitor the image is sharper than on a 14" TV!
Get your Atari emulator
here. (I recommend Winston). This is NOT warez. It's simply abandonware from an almost forgotten era
Sorry for the OT but I thought someone might be interested..
EDIT: Search for Colonial Conquest on that site and you'll find it. Along with almost any other game ever made for the Atari ST/STE