Thank you; this is very helpful.

>NETSTAT -ab will give you a list of all open ports on your systen as well as the process name. Look for anything that has :443 in the port section of the IP and it should help you find the culprit.
>
>On a desktop machine I'd suspect Skype, which can take over port 80 and 443 if you let it. If it's a server that's not likely though, but there may be some other HTTP server running on the server that *is* using that port already. Ports cannot be shared easily by multiple applications.
>
>You can set up multiple sites on IIS using the same port if you use host headers (ie. custom domain names for each site), but IIS only supports 1 SSL connection per port per IP address.
>
>+++ Rick ---
>
>>Hi,
>>
>>I am trying to install a web application on the customer web server. The customer asked that I set up port 443 for this Site. But when I do and try to start the site I get the message that "Another Web Site maybe using this port". I can set up any other port # but the 443. How do I find out what site is using this port 443 (I checked all sites in the IIS and none is using this port, as far as I can see).
>>
>>TIA