No problems in the log files is definitely a good thing!
Just about any process is painfully slow: loading applications; switching screens; loading webpages; switching users; start up; shut down; etc.
I haven't really paid any attention to the HD LED, but I can hear the HD working feverishly very frequently and when I wouldn't expect it.
Is it possible that the Norton Internet Security with three users is causing this?
Something else just occured to me...I wonder if she has enough memory? The machine is an HP Pavilion that is only a few years old. Could lack of memory be the problem?