Number one possible reason for unpredictable and (or) unstable drawing behaviour

For those of you having problems opening  acad drawings, which causes Autocad to crash this is the number one possible reason.
"Large Drawing Coordinates" !!!
Note it, try to understand it and the most important find ways to resolve it!!!
The following is official from Autodesk.
Errors or performance problems when working with objects in large coordinate space
Published date: 2006-Oct-12
ID: TS1059929
Applies to:
AutoCAD® 2009 AutoCAD® 2008 AutoCAD® 2007 AutoCAD® 2006 AutoCAD® 2005 AutoCAD® 200 AutoCAD LT® 2009 AutoCAD LT® 2008 AutoCAD LT® 2007 AutoCAD LT® 2006 AutoCAD LT® 2005 AutoCAD LT® 2004
Issue
When you were working with geometry drawn in large coordinates, you either received modeling operation errors or you noticed general performance/stability problems.
Solution
This behavior occurs because the size of the coordinate values involved in the mathematical calculations push beyond the computer processor's capabilities to calculate. There are many modeling operations in AutoCAD that will not work correctly at large coordinates because of this limitation. When objects start to exceed 100,000 or 0.000001 units in precision, the mathematical calculations are at risk to push beyond the processor limitation. However, the limit will vary from machine to machine.
To correct this behavior, you must move the objects closer to the origin.
You might also notice an improvement by running a 64-bit processor. However, you will still encounter limitations at some coordinate values.
Note: Many Autodesk programs are not supported on 64-bit operating systems, but they will run on 32-bit operating systems with compatible 64-bit hardware. Use of 64-bit processors to improve large coordinate performance is not officially tested by Autodesk. You should evaluate and test all hardware to make sure it meets your needs before making any purchasing decisions.