rebooting after hours of flight

My Computer reboot it self sometime after long hour of flight or when i quit the sim.
Anyone know why?
I was flying to Charle de gaule from Dorval and half way over the sea it rebooted it self... i was doing it in real time. (i had some time to spare.) over night flight (real local time, real wather) , I was to arrive at destination at 5 am. for the sun rise(using GPS). I was so exited and then i was so pissed....
I love that sim... but if it crash on long flight....
please help.
ps I am a noob.... make it simple...
Fox
Anyone know why?
I was flying to Charle de gaule from Dorval and half way over the sea it rebooted it self... i was doing it in real time. (i had some time to spare.) over night flight (real local time, real wather) , I was to arrive at destination at 5 am. for the sun rise(using GPS). I was so exited and then i was so pissed....
I love that sim... but if it crash on long flight....
please help.
ps I am a noob.... make it simple...
Fox