Hey Carbon, Volt & CaptainAanderson -
Thanks so so much for the great replies folks, great explanations and wording there.
Ok, well, that does put my mind at ease and so after a bit more reading tonight I think I might order it online.
One question that I have from what captainAanderson said... does the AI team up in a game and then break alliances with its co-AI?
Just to give you a background as to why I am asking all these trivial basic questions. I do not play games. Not on any consoles or PCs. I used to be into Unreal Tournament and Red Alert many moons ago and prefer a good tactical strategy game. In fact I love chess! When I heard about Sins I thought it sounded like a great game and with so many great reviews it seems a certainty that it will be the game I enjoy. Afterall, it will have to be as I dont play anything else. So yeah, not being a regular gamer but having a PC that will cope easily with modern games I wanted to find something to occupy some time.
Sorry if I ask any further questions for which the answer would normally be "just play the game and you will find out". But I am not a hardened games player and want to have a good grasp of the game before I spend money I have not got to buy it.
Cheers again folks and I welcome any other replies. 
PicardsRug