Turn the Ribbon back on

Hi,

I have a spreadsheet and could not see the tabs at the bottom of the screen. I tried to show the tabs by going into View and clicking View Full Screen (or something like that). Now the ribbon has vanished and I can't turn it back on. I have an Excel book that suggests clicking tabs or clicking the button next to the help button but I have no tabs (I can see the bottom tabs now, but no tabs to do with the ribbon) or buttons showing at all.
I also tried Ctl+F1 as suggested in the book but it does nothing.
I have a report that I need to get out urgently so any help would be very much appreciated.

Thanks very much

Dave