Try turning off as many of the programs that are running in the background as you can.
Screen Saver, Virus Scanner, any other games, music, etc. These take up system resources, that you'll need to run the sim. Check your FS settings and try lowering the sliders under the Display menu. It's a compromise between good performance/framerates, and decent graphics. But, you'll have to decide what you can live with.

Also, do a system maintenance, using Scan Disk, Defrag, and System Clean Up.
(You should do those 3 at least every month, anyway, to help your system be more efficent.) These are located in your Start menu.
"Start>Programs>Accessories>System Tools".

And, go to Internet Options in the Control Panel and clear out History, and your Temporary Files. They take up allot of space if you don't stay on top of it.

You didn't list your system specs, so it's hard to say. Maybe you don't have enough RAM, to render the new graphics correctly. It really sounds like you don't have enough system resources available, so your computer crashes.

These are all things that you can do, before starting the sim to help the performance. They are little things, but they all ad up and help.

8)