I wonder if the battery is completely dead, and it just left the last screen on the display? Weird, but it would match the symptoms you're seeing.
Do you have the Connect software installed on the laptop? If not, it might not have charged the battery, even though it was showing that it was connected. That would eventually run down the battery. When you plug it into the computer, does the red light above the power switch light? If not, it's not charging.
If you've got the wall charger, or can borrow one that might be worth trying.
Also, if you have a card installed, you might try resetting the Reader after taking it out. It might have somehow become corrupted.
Finally, you might try the hard reset described here:
but you'll apparently lose any content on the reader.