No-where on this thread do I see that you have attempted to re-flash the player using V2 Final using the serial cable and the updater to get the player back to a known state using standard software. Also, I don't know which version of the player software you were using prior to this problem. Were you using V3.xxB releases, by any chance?

Have you done anything recently to the player, ie. open it, install a new disk, try a memory upgrade, anything else?