Hello! I wanted to report that the device is now working--thank you, fekhner and Iņigo.
What happened was that I used a Dynex Mini Memory Card Reader/Writer to attempt to delete global.db via Mac OS 10.6.8. Mac OS gave me an error message and this attempt apparently deleted the contents of the memory card (!); I couldn't eject the volume and Finder crashed, so I had to power down and remove the card. (I suspect this was my OS but am not certain.) However, when I put the (now-empty) card back into the DR800 and restarted, it started up fine, only a very very brief period of reindexing. Now when I plugged in the USB cable I was able to put my ebooks back on. (This time I put on fewer ebooks; I already turned off the thumbnails.)
Anyway, thank you again! I am already reading some text files with much pleasure.
