gnus, imap and gnutls in win32

I’ve been trying to get gnus working in emacs in win32 for the past few days. There were a number of obstacles to overcome:

1. Install gnutls
2. The gnus README.w32 says gnutls should be installed and in the path. I found that it must be in the windows system path to make it work. Setting the path within emacs was not good enough. So add C:\Program Files (x86)\gnutls\bin;C:\Program Files (x86)\gnutls\lib to your system path by going to Start/Edit System Environment Variables then click Environment Variables and edit Path in System Variables
3. you need to edit the emacs variable gnutls-trustfiles to point to windows paths to .crt files. by default it had paths to unix locations. The only way I could find to get these files was to install cygwin and then make gnutls-trustfiles equal to ("C:/cygwin/usr/ssl/certs/ca-bundle.trust.crt" "C:/cygwin/usr/ssl/certs/ca-bundle.crt")

Unfortunately these last two steps were not obvious to me and it took me quite some time to work through them.
Tip: if you need to debug gnutls, try setting (setq gnutls-log-level 50).
Now all I need to do is learn gnus!