With a dual core AMD CPU and Vista, you are going to need to run the game in compatibility mode to force the operating system to keep the game on one CPU. It is a bug in the AMD CPU we happen to hit.
Right-click on the Aces High II startup ICON, then select "Properties", then select the "Compatibility" tab and check the option to run the game in compatibility mode and select "Windows 98/ME" compatibility mode.
That is the only way the game has a chance of running stable under Vista with a dual core AMD CPU.