Unable to finish tutorial flight

As I made an error by adding the STAR and transition to the original flightplan, thus having it twice, I tried to remove the waypoints, only ending up deleting the plan...So I attempted to add the STAR and transition by hand...I was already past the initial fix of the STAR, LRP, and the sim promptly froze...No chance of shutting FSX down, had to restart the machine with the reboot switch... couldn't even get to the task manager or back to desktop...I'll need to have a look at this again. Has anybody else experienced lock ups ar CTDs with en route changes to the flightplans?Andrew