How much Ram do you have the minimum to run Bryce 7 Pro is at least 1 Gigabyte I have 4 Gigabytes of ram and it works pretty well. Do you own a Windows Computer or a Macintosh pc because Bryce has issues in Mac osx Lion (it will not work) and in snow leopard it will not import pictures so you would need either Bryce 6.3 or Daz Studio to transfer over to the different platforms. Once an image is made into a .br7 file it will not work in lower versions (even 6.3 so use it wisely) What type of Train are you making because I have a free download of the international flying scotsman in Bryce 7 you can use it if you like.

Try dimming the lights a bit if it keeps crashing you can do this by lowering the intensity and specular.

Good Luck

Karl