crash to desktop, no warnings or errors.

Hey guys - first of all my setup.C2D e6600eVGA 7950gt2 gigs ddr2 800All settings maxed, besides traffic.Driver settings are 8xS AA and 16x aniso.I always fly on a fresh reboot.I only fly with delta VA ACARS, and RADAR CONTACT.Problem is as follows.Without fail, about 5 minutes after starting a flight, FS9 minimizes to the desktop without my doing anything. I always just click back to get back to the game.I can't give a probability of CTDs I get, but it happens enough to upset me. maybe 1 out of 7 flights, I will wake up to finish my flight and fs9 will be shut off w/o warning. No errors are displayed. It is just off.Any ideass!Thanks, Dan