I bought this laptop in September 2007, then all of a sudden it started giving trouble to power up. The battery and the charger work perfectly in another Aspire 5100. I have to really fiddle around with the adapter for the laptop to get AC power, and it wouldn't start up unless the charger is plug in. Once i get AC power i could power on he laptop fine, remove the adapter from the laptop and it will operate off battery power fine, but it would not start up on battery power, even if the battery is fully charged. Any help will be appreciated. thanks.