8.2 How do I open attachments in Gnus?

In your HOME directory create a file called .mailcap, with contents like the following:

application/zip; "C:/Program Files/7-Zip/7zFM.exe"
video/*; "C:/Program Files/VideoLAN/VLC/vlc.exe"

Warning: Associating MIME types with start or other generic Windows commands to open arbitrary files might seem like a good idea, but it leaves your system as open to attack as Outlook Express was at its worst. Especially dangerous is associating application/* or */* in this way.