Ipod generation 1, updated ipod software version 5.1.1 and now my ipod is dead..

I have an ipod generation 1 since 2005 and it works perfectly till yesterday when i receive a prompt from iTunes store (after my last login 6 months ago) reminder/alert to update my ipod software version to 5.1.1 in which i did and just after i updated the software my ipod went dead..

The message appeared "Please Wait..Very low battery.." However, when i plug it into adapter charger i'll see the normal screen, but the message appear when i use the cable to connect to my lappie....Urgent help! Thanks.