When you have tested a newer trial version of ARES Commander and removed this application, then we recommend to run the original setup of your older, purchased ARES version again. This is required to register the DWG and DXF extensions correctly again and to open these files with the CAD-application from the Windows Explorer automatically. You can use the repair option of the setup here.
The latest setups can found under:
For older setups please mail to [email protected]
If you have saved files in latest DWG format with the latest ARES Commander version, then you probably have to save them via the SAVEAS command in an older format version (supported by your current purchased application) again. Otherwise you can't open the files of the newer DWG format in your purchased ARES Commander version.
If you have only opened the files in latest ARES Commander, the DWG file isn't touched and it should be still the original format.