All you should need to do is push in the paper clip until you feel it press the reset button, then flip the power switch off and back on. If that doesn't work, the hard reset is next.
And these things are like little specialized computers -- when they freeze they stay frozen until you reboot or reset them, so it will stay the way it is until you reset it. Again, the hard reset will delete all your books so you have to reload all f them to the reader.
