Rande, this model comes directly from National Instruments. The best way to simplify this on your older computer is to replace it with a "box" representation. Just create an extruded box of the same size and use it as the primary component in your design. The electronics only need to be packaged in most cases, so using over simplified versions is a quick and easy way to get this done.
Someday I'll have to record a video of the old electronics packaging demo I did as a FIRST kickoff workshop years ago. The strategy was the same, replace the heavy cRio and Jaguar models with lightweght representations to simplify the packaging process in CAD.
-Scott