How do you open port 443 on Windows 98SE

I have a system that connects to the internet directly through a cable modem. No firewall are installed. Windows 98SE.

I cannot view secure web sites. For example, I cannot use any of my webmail sites (except Yahoo! for some reason). Banking sites also do not work.
I have no router. I am connected directly through a cable modem.
I am told to open port 443. HOW DO YOU OPEN PORT 443 in Win98se.