To run Home Assistant on Microsoft Windows installation you need to install Python first. Download Python (the latest version of Python 3.6 is recommended) for https://www.python.org/downloads/windows/ and follow the instructions of the installer.
There may be alpha or beta releases of Python listed on that download page (marked by the letters
b in the version number. Do not use these versions.
C:\...\> pip3 install homeassistant C:\...\> py -m homeassistant --open-ui
For autostarting Home Assistant please refer to this guide.
Check this video for the installation on Windows 10.
The Microsoft Windows platform is not a primary target to install Home Assistant. Also, not all tools and third-party modules will work.
To update Home Assistant, stop it and then run:
C:\...\> pip3 install --upgrade homeassistant
Then start Home Assistant.