I occasionally had the issue where changing layouts PS to MS or visa-versa caused AutoCAD to crash.

I found that someone had changed the WHIPTHREAD setting to 3... I changed it back to 1 and the crashes went away

(Now I just have to find out WHO the culprit is LOL)

WHIPTHREAD

Type: Integer
Saved in: Registry
Initial value: 1

Controls whether to use an additional processor to improve the speed of operations such as ZOOM that redraw or regenerate the drawing.

WHIPTHREAD has no effect on single processor machines.

0 - No multithreaded processing; restricts regeneration and redraw processing to a single processor. This setting restores the behavior of AutoCAD 2000 and previous releases.

1 - Regeneration multithreaded processing only; regeneration processing is distributed across two processors on a multiprocessor machine.

2 - Redraw multithreaded processing only; redraw processing is distributed across two processors on a multiprocessor machine.

3 - Regeneration and redraw multithreaded processing; regeneration and redraw processing is distributed across two processors on a multiprocessor machine.

When multithreaded processing is used for redraw operations (value 2 or 3), the order of objects specified with the DRAWORDER command is not guaranteed to be preserved for display but is preserved for plotting.
Hope this helps anyone that may have the same prob.