Hi bubble-head,
This seems a bit strange, but there's a couple of things I'd be tempted to try.
I know that you mention that this is after you've charged the Reader - but what you describe does sound like this could be a really depleted battery. If the battery is completely dead, then it is possible (because of the way that e-Ink screens work) for the last image on the display to be retained. This would give the impression that it is not switching off. If this is the case, it is well worth giving the Reader a good 3-4 hour charge. (If you're charging with USB from your computer you need to make sure that the computer doesn't 'go to sleep' during this time otherwise charging will be interrupted - if you have the mains charger use that as it is much more effective at restoring a badly depleted battery).
If you do have battery charge, there area a couple of other things you could try. First, see if you can completely shut down the PRS-505 (and see if it behaves normally once you re-boot it). To shut down, from the home menu choose 'Settings' then 'Advanced Settings' and then 'Device Shutdown' (you have to press the bookmark button to finally confirm the shutdown). Then switch the unit back on normally - it will just take a bit longer to turn on while it re-boots and see if it then switches on and off normally.
If this doesn't work, I think I'd try a soft reset (press the reset button in the hole on the back of the Reader and then slide the power switch), and if this doesn't work then try a hard reset (although a hard reset will erase all contents, so make sure you have any eBooks etc that are on the Reader also stored on your computer so that you can transfer them to the Reader again).
Instructions for a hard reset are in the FAQ section for the PRS-505 on Sony's support website.
Hope this helps?
