My favorite computer game of all time is Rome Total War, and I must announce to the world that I have uninstalled Medieval II after just a couple of weeks. It is a fine game, but it crashes constantly, and the support forums basically consist of well-meaning unpaid volunteers saying “It’s your hardware, or you have a conflict with another game.”
Well, I installed it on a brand new MacBook Pro (in Windows), with no other games at all installed. It’s hard to imagine a more clean, stable environment for a game, and it has been terribly frustrating to find M2TW so very fragile.

Update - I’ve had two commenters say “Get a new PC.”  I have a brand new MacBook Pro, Core2Duo 2.16 GHz machine, that runs other games beautifully.    If that’s not enough to play this game well, then the developers are fools.