CTD while in descent going through FMS

Hello All, Well did my first test flight with the 737NGX all went well until I was in my descent into SEA from SJC and I was going through the FMS to make sure I got things setup just right for my arrival when all of a sudden the sim freezes and then shuts down and I get a Fatal error that FS had to shutdown wierd issue. My specs are as follows: Windows 7 64bit Asus P7P55D-E Pro MB I7 870 2.93 oc to 3.8mhz 250gts 1GB DDR3 video card and 8gigs of memory and 2 1tb hard drives hope this hope blueskies. Brett Wells