How can you not own the original Col????
I even bought the windows version a decade ago for a 2 euros or something, when it was dumped all over the place.
Colonization can be downloaded from different abandonware sites, both in windows and dos version. Windows version won't install on 64bit windows versions so you need to download a patch for that as well. Also available from fan sites. Easiest way to go is the DOS version and DosBox imo.
Googling this is the
1st site I encounter, but you'll find other sites as well without a doubt. Chances are you'll have to adjust the CPU cycles setting in the dox box config file to get it to run smoothly. I changed 'auto' to 'max' and it runs fine for me. Others seem to have success with 7500 & 12500.
Another option is to buy it from good old games (
www.gog.com) They adjust old games to run on new computers. It makes installing easy and all games from GOG are DRM free, also a good option.