ProSystem is the best emulator of Atari 7800 game console, running on Windows system.
It has been written by Greg Stanton, see http://home.comcast.net/~gscottstanton for details.
Here is a port on Pandora of my Wiz port version.
Many new features have been added compared to original version.
A full working PND version and source code are available on my web site : http://zx81.zx81.free.fr/