The dell 910 is a 9" LCD netbook from dell. This 910 came in and won't power on off AC or battery power.
It uses a cable style dc jack that plugs into the motherboard and the dc jack itself is soldered onto that cable.
When taken apart the red voltage wire has come undone from the dc jack. This can happen naturally on it's own or it could have been dropped or mishandled.
In this case you could try to re-solder the wire or replace the entire dc jack cable.
Once replaced the laptop works like new again.