Previously, as my wife and I are the only two users and we both use the same user account, it used to finish booting automatically without having to click on the 'user' icon.
I note also that since installing the game, my 'Welcome' screen now wants me to click on my user icon to get the computer to finish booting. It says 'Waiting for other civilizations', but there is no movement on the screen, and then after about 20 seconds the screen goes black and the computer reboots. I have actually now reached a stage where it crashes every time I try to save. I have not yet tried Warlords or BTS, which came with the pack, although they are installed. I have only played one game of Civ IV (Not yet able to finish it) but I find that it keeps crashing, so that even with the 'auto save' every 4 turns, I have to try to save after every turn so as not to have to go back and do stuff again.
I have recently installed Civ IV complete, after having unresolvable problems with Civ III.