I have Pro/E Student 3.0 as well and when I'm heavily using it, it crashes like that. Some menus stop functioning properly,too. I recommend that you defrag your hard drive (even if Windows says you don't need to). I did that to mine and it fixed it. If you're in Vista, you'll need to go to the command line and type "defrag c:\" to force a defrag; Vista doesn't have a GUI utility like XP does.