I've got an inspiron 6400 on xp and recently its come up as showing battery not present on the power meter. I did the bios tests to check everything was working and it detected the battery no problem and said it was charged and all 5 green lights light up on the battery itself. When i pull the power cord out the laptop shows as still running on ac power but shuts down within a few minutes, I don't want to have to splash out over a hundred ££ on a new battery as I'll just buy a different laptop or could it be drivers etc?? I tried updating the bios but it wont do it as it says make sure battery and ac adaptor are inserted first and doesn't think the battery is!