Double click My Computer. From the View menu, select options and the File Types tab. Scroll the list of "Registered file types" and select "Folder". Depress the Edit button, and select Explore. Press Set Default and press Close and press Close.
If you want to change the Open behavior, select Explore and press the Edit button and select the text in DDE Message and copy it to the Clip Board. Click on OK. Select Open and press the Edit button. Paste the Clip Board contents into the DDE Message and click on OK.