Hi edelting! I have Adobe Digital Editions installed and everything is working fine. I had installed ADE and downloaded a trial book before I got my Reader, but that shouldn't matter. Have you tried the tips above? (Leaving it plugged in in case it's the battery, holding the reset button and cycling power 5 times, and contacting Sony Support.)
I hope you'll have good news to report soon!!
Justice Strike, was yours truly dead? ;/