I added the following to installation.txt:

-------
If you are using the Roundup Windows installer on a 64 bit system and
you get the error message::

  "No Python installation found in the registry"

you need to install a 32 bit version of python. The 64 bit versions
use a different registry key that the installer doesn't detect. See:
http://issues.roundup-tracker.org/issue2550718 for details.
--------

under Prerequisites.

As of 1.5.0 (IIRC) PyWin isn't needed unless you are running it as a
service. So demo.py and a manual start of roundup-server should work.
See issue2550827 for details.

above is part of commit: 7ea6bbf4286c