CREO KEEPS CRASHING

I am using Creo Parametric Release 6.0 and Datecode6.0.4.0

THE PROGRAM KEEPS CRASHING. I AM USING A CERTIFIED VIDEO CARD (Nvidia p4200) BUT WHEN MY MACHINE SITS IDLE FOR ANY LENGTH OF TIME A GET AN ERROR OR A BLUE SCREEN. It didn't use to do this. I am running the latest 512.18 display driver. It's hard to get any work done.