Outlook 2003 email notifacation envelope

We have come accross a computer wthin our network that has this problem of not being able to see the outlook envelope in the bottom taskbar. Also the email notifacation pop up notifier does not work. We have been into the usual setup area and all of the options are marked and so should work. Very frustrating having to go into your outlook to check for mail all day!!!
Any further ideas please???