I think you are simply low on memory, due to too high settings, a memory-hungry airplane, too many AI planes, and a combination of all of this, which might just too much to handle for a 11 years old sim running in 32 bit.
- You can try to lower your settings, especially the scenery radius, the autogen complexity and max texture size
- You can try enabling DX10, this will save a bit or memory, due to how Windows video driver work.
- You should really consider Prepar3D V4, which doesn't suffer any of these issues, as a 64 bit sim.