Won't load 2nd session ..... error!

[grizzard]

I load FSX and the first flight always goes well from take off to landing .. say from 18 to 24 fps. Second flight I change the airport, the weather, the plane or the flight plan and I always get 100% load and then it errors out and asks it I want to send a message to MS. If I attempt another 2 or 3 times it MAY load ... but usually I have to exit FSX, reboot the computer and reload. My cache is on a separate drive ... 3 MB. System is an AMD X2 4400 O/C to 2500 (runs cool), 2 MB OCZ Ram, MSI Nvidia 8800 GT 512mb (locked down to 100 mhz). I have SP1, SP2 & use Nhancer which works nicely.  I am just doing Free Flight usually with the AOPA Cardinal, Cherokee Six, or Commander .... mostly dead reckoning .... just getting used to the controls and feel. Most of my settings are on Ultimate except weather. I don't think I'm taxing the system.

Any thoughts or ideas appreciated.  :) 8-)

Jim