OK, Believe me or not, I've had my system lock up on me also. It happened just a few minutes ago, and when it did, I realized it had happened to me once before. I figured it was due to my impatientence at how slow rosity is at switching between pages. Both times I was clicking the sidebar down arrow before the page had finished loading. While this did not crash my computer, I did have to do a ctl alt delete and endtask of the renderosity stuff that was not responding. And I also could not switch to any other sites till I ended them. So I guess I've got a similar problem.
:(

ps I use windows xp, 1 gig ram, amd 2800, and norton anti.