I suppose we could try a real crash - just unplug the electricity cable to the PC while we are in the middle of a quiz 
I wouldn't like to do that on one of my main computers, but I might try it on an old machine that is no longer "state of the art" and which I have abused before in this kind of extreme computing experiment.
Here it is starting up ... oh, Windows 98 !! .. start the browser (IE 5.5) ... go to your site, log in as a student, access the QuizPort, click "Resume", finish the attempt at Exercise 2, here comes Exercise 3, select a few answers, click check (30%), now pull the plug (!!) ... black screen.
I restarted the computer and let it do the disk checking that it likes to do after a crash. When I went back to your site and logged in again as a student, the "Resume" button took me back to the start of Exercise 3, which is what I expected. Great 
. I finished exercise 3 and the menu of quizzes was displayed.
From what I have seen to far using my computers, everything looks normal. But obviously the students had a different experience so I look forward to receiving info more information tomorrow.
regards
Gordon