did you open unit? how your problem happens? If you did not open unit and never try to replace battery them your battery is probably dead. So you need new battery, open unit, replace battery, localte that Intel chip. Conenct serial cable, connect power and short cut ground with U19 chip pin 28. Them you should see something about flash format, unit reboots and boot menu should show. you probably need to short cut circuit more times to get boot menu. them flash via xmodem firware version 06.61.05.0009, boot, save config and reboot. unit should be ok.