Acer N35 disappearing Calendar

Hi all,

New to the site so I am sorry if this is in the wrong section of if it has been answered before.

I run an ACER n35 and am very happy with it (although the GPS gets a bit confused when I drive into the middle of a field). Anyway, the calendar has started a habit of disappearing. When I switch to the calendar, I get a sketch-image of the PDA then the entire machine shuts off. Recurring events and reminders are still working though. Is this some form of security sytem that I have turned on by accident?

I am wary of connecting it up to my main computer at the moment incase there is something contagious in it. Everything else seems to work just fine.

If any of you guys can help it would be appreciated.

Many thanks