I run AutoCAD 2009 on this machine as well as DWG TrueView 2013. TrueView did an excellent job for me today in converting hundreds of DWG files from 2009 to 2004 so some other 2005 users in this office can access them. But in the process of running this, TrueView seems to have highjacked the DWG file association within Windows and now when I click on any links in Explorer or emails instead of getting AutoCAD I end up with TrueView. Is there some method to stop this default behavior?
If Pendean's answer did not work, try this:
Open your file manager (NOT IE).
Tools -> Folder Options (XP).
Tab over to "File Types".
Scroll down until you see DWG.
Highlight and Delete.
Open your file manager.
Double click on a DWG file.
Browse for and point to ACAD.exe.
We had the same problem here.
I do not remember if changing the association option worked here.
All I do remember is that it was stubborn to unlink from true view...
I think that will only be a temporary fix. They have my computer in another lab today so I cannot test it. But I think that will only hold true until you run True View again and it will again highjack the file association. I found that if you just run AutoCAD again it will grab the file association back. It's a constant tug of war. Thank you again Autodesk developers for making life a little more miserable.