There is no warranty of any kind. Please assume that any software you download from the web (including this site) contains viruses, trojans, etc.
To start Electric Astrolabe as a screensaver I wrote a wrapper that changes current directory to a place where I installed Electric Astrolabe and then starts appropriate dos executable. To change directory and executable to something else, edit .scr file in hex editor or recompile .c file.
It most likely will not work with Windows Vista.