FS9 crashes to black screen

Hi
Just got round to buying a new PC so thought I would treat myself to FS9. However when I play, every time I use the esc key to pause or quit current flight, I get a black screen and the egg timer follow by the message telling me that FS9 has stopped working and asking if I wished to send an error report to microsoft (did this the first couple of times).
It also occasionally does this when I hit alt to either bring up the menu or if I have been in a meanu item and I am returning to the game.
Any help with this would be most appreciated as the sim looks fantastic, but I can't get anywhere with it as it keeps crashing.
Just got round to buying a new PC so thought I would treat myself to FS9. However when I play, every time I use the esc key to pause or quit current flight, I get a black screen and the egg timer follow by the message telling me that FS9 has stopped working and asking if I wished to send an error report to microsoft (did this the first couple of times).
It also occasionally does this when I hit alt to either bring up the menu or if I have been in a meanu item and I am returning to the game.
Any help with this would be most appreciated as the sim looks fantastic, but I can't get anywhere with it as it keeps crashing.