Stuffit work on all platforms, WIN, MAC, LINUX etc. so it is not necessarily a MAC file.
Also Stuffit preserves files names so the;
.xxx.sit
does not imply a virus, this is quite a normal option for Stuffit behaviour.
If you need the software try:
http://www.aladdinsys.com/expander/winlogin.html
[ 09 August 2001: Message edited by: Icarus ]