CaféAuLait
This Space for Rent
Why fly for seven hours?
To burn off fuel for a crash landing?
Or was everyone dead from decompression, and the plane was just flying itself?
I don't think they were dead from decompression. The plane was flying a flight path which would have required precise input or maneuvers by whomever was piloting the plane.
Huffpo and CNN explain it pretty good in the articles here:
Missing Malaysia Airlines Flight 370: Evidence Points To Takeover
Pilot: Whoever changed flight path was an expert - CNN.com