SMAC is not exactly the most XP friendly game it can be fickle... I finally got it working on my 120 GB AAO, 1.5 GB Ram. 1. Right click on the installation file on the CD and select windows 98 compatibility. 2. Run the installation file. At this point I thought for sure it was going to require more tweaking... (considering the many different combinations of components I have tried so far) nope it worked immediately. I then grabbed the [url=http://www.firaxis.com/games/downloads.php]SMAC v4.0 update[/url] and installed that. The game seems to work fine. I checked the terran.exe settings and for compatibility mode it has the following selected: Run in compatibility for Windows 98/Windows ME Run in 256 colors Disable visual themes Turn off advanced text services for this program I did not install the XP compatibility patch (and as SMAC is working now I'm not sure I want to risk it). For the screen to show properly you will need to change your display to 800x600. :D Hope this helps.