I think my computer must just have been in a bad mood yesterday, it's working just fine today. There wasn't anything else running (except antivirus and firewall, which I have to leave running since I'm on a campus network and unplugging computers makes the resnet people unhappy, for some reason). I've been rendering pieces of it at a time today and saving in between--slower, but if it crashes again I don't have to start from the beginning. Layering clouds was the original plan, but I think I'm gonna wait for a particularly masochistic mood to strike me or until I get a faster processor (or the funds for a computer just for rendering, as Kemal suggests), I think it would take about a week to render something like that ;)