Beware of Windows Vista and its sleeping ways. I have come across students who have found PCs asleep and when powered on they are back into the previous users account. This means open web pages (like email accounts, facebook, myspace etc.) can all be accessed as well as the users email account.
Why does this happen? Once again Microsoft has done something amazing. It has redefined the world wide and well known OFF button.
Without researching and testing on real users, they have gone and defined the OFF button to a sleep button (above figure). Therefore when students hit this button their machine sleeps and does not shut down. The sleeping Vista is then waiting for the next student to wake it up and carry on with the previous users account.
How to avoid it: select the ARROW to the right of the SLEEP (not OFF) button and select LOG-OFF OR the best and easy way is to hit CTRL+ATL+DELETE and select LOG-OFF
Beware of the Sleeping Mountain (Windows Vista)! You have been warned !!!
When changing the button to a Power-off button it will look like the picture below.
Many thanks to Gareth for pointing out the problem.