Hi Anne,

after downloading the "Avis Fits Viewer" from http://www.sky-watch.org/fits/avisfv.zip, you have to unzip this file. You will find an application called "avis.exe" inside. Run this application by doubleclicking it. You can now open a FITS file by using the menu. If you like, you can then export standard BMP or JPG files.

Come back here if you still have problems.

/ Lars