Thanx for the Reply
The OS is Windows 7 Professional
Drawing (*.dwg) files are able to be opened by double clicking the name in Windows Explorer which in turn launches Progecad 10.0.10.8
Normally, in both Windows XP Pro and Vista Business Operating systems. (Same File used for test)
In Windows 7 - double clicking the drawing file within windows explorer returns a
Runtime error
Program C:\Windows\Explorer.EXE
R6025
-pure virtual function call
Then closes Windows Explorer and Restarts Windows Explorer. Progecad does not get launched as for the other operating systems for the same procedure