Aloha,
First, if'n you can, check the game's web site and get the patches
(there will be many). The latest alliteration of this game is Civ 5;
so your version has been around awhile Next you need to visit the
fan site and make certain your computer has the horsepower (not what
the box sez) . Meyer's games are notorious for needing massive amounts
of resources and for being designed to max out 'next year's chip' .
The best example is when CIV 5 came out and purty near everybody
discovered it wouldn't run on 'uber' machines graphics without
problems, freezing and crashes. It took a year and a half to get those
problems resolved.
All that being said, Civ 5 is incredibly challenging; significantly
better than 4.
Good luck getting 4 to run. it is well worth the effort.
- redvet