Well.... On windows best bet is to just open a command prompt where you will see a plain looking prompt; in my case
Now, unless you have a copy of Python installed, you can use the built in calibre python environment.
Code:
calibre-debug drmcheck.py followed_by_name_of_epub_file_to_check
as an example
Code:
calibre-debug d:\Downloads\drmcheck.py "Documents\My Digital Editions\$20_Per_Gallon.epub"
ePub ebook, Adobe Digital Editions encryption.
(the path before the drmcheck.py is the location on my PC of the script)