Thanks so much everyone for this. My Kindle has been irritating me for some time (it is almost 4 years old) - slow to respond, sometimes refused to search when I wanted to buy something, then this morning it froze altogether and I truly thought it had had it! Consulted this forum and proceeded according to advice of others. Held down the on/off switch for well over 30 seconds, then it turned off, waited quite a while without touching it, then the screensaver tree and reader appeared, with a progress bar beneath. This almost reached the end, then stopped, but I told myself patience was everything and in due course it put itself through several processes of internal digestion and eventually restored itself to apparently prime condition. I can now access my list of books, search for new purchases, "turn" pages swiftly, and have just downloaded a freebie classic which appeared speedily on my home page. So just be patient - presumably like all computers Kindles get themselves in a twist every so often and need a re-boot. Hope this helps others.