My Computer has froze on 'Cant display the web page'?

[GeorgiaB!]

Ok, right, basically, i was just browsing on internet explore on my other computer (its windows 7) and it was all working fine, i was on facebook and watching a film, then suddenly the screen went full screen (like it does when you press F11) and went on the page saying 'internet explore could not display the web page' although the sound was still playing, so i turned it off and back on again, but every time I turn it back on, it just goes straight back to full screen and that page. I can't click anywhere. The task bar and everything has gone. The only thing i can do is go on CTRL-ALT-DELETE and it'll take me to that menu, but that's it and it doesn't help. I've tried everything, turning it off and back on, turning off the plugs and leaving it for a while, trying to close it with CTRL-F4, left clicking and all sorts!
PLEASE HELP! What do i need to do!?
Thanks! x

P.S. When i turn it off it comes up with 'cannot exit' as a quick message, in case that helps.