IIS setup - Secure Key

I don't know if anyone can answer this but here goes...

I had to renew my Secure Key for my order online web page.

I am running a version of Internet Information Server that is earlier then V3.0 I have installed the key OK and the status says 'key is complete and usable'.
 
When I checked the website and tried the Order Online page it said 'Secure Certificate Out of Date'.
I checked in key manager and the old key had the server ip address assigned and the new key didn't so I assigned the server ip address to the new key using the same setting that were on the old key.
 
I also ticked enable SSL - 'Require secure channel when accessing this resource' on the Directory Settings, Secure Communications tab,
when I clicked apply it asked if I wanted to apply the new settings to the default website so I click Yes.
 
After doing this when I tried to browse our website I got the message:
 
HTTP Error 403
403.4 Forbidden: SSL required
 
This error indicates that the page you are trying to access is secured with Secure Sockets Layer (SSL). In order to view it, you need to enable SSL by typing "https://" at the beginning of the address you are attempting to reach.
 
Please contact the Web server's administrator if the problem persists.
 
I then unticked SSL and applied the setting to Default Website.
I can now view all http: pages but not https: pages I get the message 'This page can not be displayed'.
 
I think the problem stems from when I said yes to apply to default website, not knowing anything about webservers do I apply the SSL only to the folders that are the SSL (https:?) area of my website or do I apply SSL to the whole website?
 
I am at a bit of a loss as to what to try next not knowing anything about website online secure pages etc so if you or anyone else
there has any ideas I would be most grateful.
 
Thanks,
 
Jason.