I accidentally selected the hibernate option to close down my computer and now I can´t get back to the standard shut down option. I go to "start" and click "close down" and the screen blinks but does nothing. The small window with the various close down options doesn´t appear. How do I get thaty screen back?

Check your power management options. Rt-click on the desktop, select Properties, go to the Screen Saver tab, and then click on Power.