FS9 Crashing when reaching cruise ALT

i have a problem, i set up for the flight CYYZ-MUHA and when the plane is around 30000 feet something happens that fs9 crashes, it either gives an error msg or just restarts the PC...my pc specs areevg 680i motherboardcore 2 duo 2.13ghz2GB DDR2 1066MHZ OCZ3 Hard Drives2 DVD +/- Burners8800 GTS Superclocked 320MB video card...so i dunno wat the problem is cuz its hard to think that its caused by the hardware...now im doing the flight in windowed mode, i also downloaded the 9.1 update and installed it as well...so far im at 33k feet and nothing has happened...i will post back what happens...if anyone can help id appreciate it..oh, FS9 is not installed in Drive C, i have it in one of the extra disks in case i need to reformat the pc...thanks