Thanks Jeremy_v for the reply, but this does not help at all, I have already read through these articles, if I may explain further:
I have been using my G4 IPod now for 18 months. The unit has worked well and I have been very satisfied with it. The battery life has been good - frequently playing for 8 hours or more. This has NOT reduced recently.
When I say "when plugged into computer with the short apple USB lead shows red for 3/4 seconds then nothing"
The LED on the IPod shows steady red, then goes out and the unit will not respond at all. The computer does not recognise that anything is plugged into the USB port (or when using any of the USB Ports - that do work with the printer, other MP3 players, backup drive, etc. ) - there is no visibility in ITunes, no possibility of RESET or RESTORE as the device does not appear to exist.
The unit is not charged, that I understand it would be, even if I was using a simple mains powered USB charger.
If the battery is now dead, I am prepared to accept this and get a new unit, but I cannot find anywhere an article or reference to "Your battery is dead if this happens......."
Thanks you for trying to help.
PaulinB