You can enable cheats by creating a shortcut to GalCiv2.exe and use that to start the game.

1. Use Windows Explorer to find GalCiv2.exe, or right-click the game in Stardock Central and select Open Folder
2. Right click on GalCiv2.exe (not GC2Launch.exe) and choose create shortcut
3. Right click on the shortcut and choose properties
4. Click in the target field and hit end, then hit space followed by the word CHEAT (no switch marks necessary)
5. "C:\Program Files\Stardock\TotalGaming\GalCiv2\galciv2.exe" cheat