Reminders/Notifications

When Running Sunbird on work computer, any reminders that I have set to Pop-up and remind me of events, tasks etc... aren't "pulling through". In other word the event will come and go and no notificiation window will pop up to remind me. Yes I have selected to be reminded, Sunbird minimized in task bar will show, however work computers are set for task bar to be "auto hidden" and we as users are unable to change. Any Ideas?