Thanks for the clear instructions. I didn't need to use them though, I found another thread which gave me some hints on how to fix this, so easy I will be able to explain to my mother how to do it when/if it happens to her reader.
Here goes, Mom's guide to fixing never ending loading
Assuming you are starting with a charged reader which is stuck on loading screen. Remove any memory cards in the reader
1. Have PC turned on and ready to go with usb cable ready.
2. Open up Sony eBook library (don't know if this is really required, but can't hurt).
3. Use a paper clip to press the reset button in the back of the reader.
4. Slide the power button as though you were just powering up the reader
5. Screen will refresh to a white reader start up screen - immediately plug in the usb cable to the reader before it moves on to the loading page. If you are not fast enough with connecting the usb cable your reader will again get trapped in the loading screen and you will have to go back to step 3. If the reader displays the USB connected screen you are good.
6. Go to the eLibrary and delete all books on the reader.
7. Go to "my computer" and you will find 3 portable drives - these are all for the reader - hard drive and two card slots. Open up the first drive (reader hard drive) and delete all files and folders possible. Some may refuse to delete, it will still be ok.
8. Eject the reader from Sony eBook Library and unplug the usb cable. The reader should now boot as usual. Try to power cycle it to make sure.
9. Books can now be added back to the reader.