installing plpython3u for postgresql 9.6 under windows 7

I've used EnterpriseDB stackbuilder to install postgres9.6 and the language-pack. Postgres9.6 is installed under C:\Program Files folder while the edb lanaguge pack is installed under C:\edb. However, it seems that I cannot create the plpython3u extension because it cannot find some necessary modules. How do I get postgres to find my python language pack installation? When I type CREATE EXTENSION plpython3u is says: ERROR: could not load library "C:/Program Files/PostgreSQL/9.6/lib/plpython3.dll": The specified module could not be found. NOTE: I already use Python 3.6 for development, so I'd rather not change the entire installation, I just want to point postgres to the proper runtime so plpython3.dll can load up. Do I have to change some environment variables?