Sorry to read about your problems. I have things like that with my Sony Readers all the time.
In my cases it always helped to do what igorsk suggested me in this thread http://www.mobileread.com/forums/sho...+frozen&page=4
in posting #58 on Page 4.
Maybe this might help you too. Don't forget to save your ebooks as soon as you get your reader shown in your Computer before re-formatting.
Hope it helps, greetings from Germany,