This is all very odd.
First disable any anti-virus software and any thing else that runs in your taskbar you don't need before running the game.
My computer specs are so far below the min on the box it's a wonder the game even gets past the intro screen. But it does, and it runs PERFECTLY!!
The min specs on the box are totally out of whack with what the game can actually run on.
I have -
atlon 700
ram 512
geforce 2 32 mb card
and only a gig left on my hard drive.
I also recommend a program called RamIdle (found here
http://www.tweaknow.com/ramidleLE.html)It can keep your ram free in case there's some sort of memory leak thing going on with the software.
Maybe that all might make a difference!