Go to Documents\Flight Simulator X Files and locate the 737-200 Captain Cold-n-Dark (KSEA).FSSAVE file - it should have the FSX icon associated with it (see attached image). Double click on it so that FSX starts and goes directly to the flight at KSEA with the 727-100 Cold-n-Dark (this bypasses the FSX Opening Screen). See if it's working fine if you start it that way.

Out of curiosity, what is you default flight?

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