Anybody know any windows based software that can read .fits files from the TESS mission.
I know there are Unix/Linux solutions - I am not in position to use these.
If you can't read them with common programs, it can be that extensions etc are used (that are very standard "things", in fact). However, you can explore and convert them with Python. Just install either Anaconda version of Python 3 (Python 2 is officially dead) and Astropy module. PyFITS is available too, but it is basically a backport because of historical reasons. You can find a lot of good/simple examples from: http://docs.astropy.org/en/stable/index.html
There is also a bunch of tools listed in TESS Software Tools webpage.
I'm a new AAVSO user so I'm a bit late on a response to your question. I have a Windows based software system that will enable you to generate and view TESS light curves from FITS files at MAST. See my recent post "LcTools for Analyzing TESS, K2, and Kepler Light Curves" in the Data Analysis forum.
See also this post:
regarding the VStar TESS plugin, work recently done to extend the Kepler FITS plugin (written by myself and Doug Welch), by Cliff Kotnik and Maksym Pyatnytsky, and deployed in the plugin manger by Sara Beck.
VStar is multi-platform, so Windows, Linux, Mac.