Dos71

you must burn the .iso file to the CDROM properly
otherwise how could you expect it to work


Anyway, who actually made MS-DOS 7.1?
it's not like M$ developed DOS71 and then released it to the public
if you look at M$ websites or search it on google
you'll find that dos71 somebody had extracted it and posted it on the web.

newdos.yginfo.net disappeared some time ago
because it hosted a pirated copy of dos71
But, Of cause, the DOS71 avail. for download is a perfect legal copy.
syschat is not a pirate website.

Why is it legal?
if you look at license.txt, you'll find that the software is released under GNU GPL Public license
so to ant extent Dos71 at this website is perfectly legal.