Lately I have been experiecing minor hiccups with some of my assemblies. The sketches of components are not showing up in the assembly eventhough the sketch shows as visible in the assembly tree. When  I hover my mouse over what is supposed to be a visible sketch, the sketch will be highlighted, but the instant I move the mouse away, the sketch will dissappear. I have included an assembly that I started on our school system a 32 bit XP system running a Pentium 4 and finished it on my 64 bit Vista system (Lenovo W500 with certified card and driver). When the individual parts are opened the sketches show up when the option to make them visible is set. The latest modificationhas a part with several colors, but the colors seem to be suppressed in the assembly.

This is the only issue I have with the assembly. Is it a hardware problem, or a setting that I have overlooked?

Thanks