Drac, Jenny, and Inland - thanks so much for your input.
Drac, the part of the information at the forum your link connected me to that I thought looked promising turned out to be for IE7 WinXP SP2. So I went to the other suggestions.
The only one, and Inland has also suggested it above, that I've had any success with was restoring IE's security settings to the defaults.
I've spent most of today messing with that. I restored the default settings to the Internet Zone, rebooted, and tried microsoft.com's https site. I got the security certificate warning page but this time, when I clicked on continue anyhow, it did. It displayed a partial page and gave me the option to "display the protected content". I clicked on that and there was the whole page in all its glory! But with the certificage warning in a red line at the top.
I found that as long as I stayed connected to the Internet, I could accesss the site without having to repeat the 1st 3 steps.
I then restored the default settings to the Trusted Sites Zone and added Microsoft to the list of sites, but it won't let me connect to the site from that zone.
I have restored my custom settings in the Internet Zone. I use that zone to surf and I will not allow just any site I happen to visit to download ActiveX controls or use active scripting.
Jenny, I am going to try and find the certificate update you mentioned and install it. After that, I'm through with this.
Inland and Drac, I was in the process of finding an alternative browser when I got sidetracked by this. Tomorrow I'll get back to it.
I apologize for the length of this post.
Thank all of you again for your help.