I've tried several times to render a scene in the ultra mode, but my render gets to between 25% to 85% and then crashes. I have no other programs running at the time. My computer is 500MHz, 128 MB SDRAM, 20 GB hard drive, so I don't know why it would crash. Anyone else have this problem? I'll wait over two hours and almost have one render, then I get the message to close down my program!