Haven't yet figured it out.
By "Not loading correctly" I mean:
1) If you navigate to the URL by typing in "http:///www.glowgirlfibers.com, or "glowgirlfibers.com, or http://www.glowgirlfibers.com" as people normally would, the home page loads without its background image--it shows just a black background, or in the case of Firefox, a white background. This occurs whether I have checked "secure post" or not for the front page.
2) In Firefox, additionally, the page's styles for text are not being applied. Instead of white type, a gray type is being shown, and the fonts are not as specified.
3) If you navigate by typing in "https://glowgirlfibers.com," everything loads correctly in all browsers. But average visitors won't do that.
4) In Internet Explorer, we have reverted to "this page has secure and insecure items." This is not occurring in the other browsers.
I feel that some setting may have been lost when I performed the upgrade, but I cannot imagine what it is. However, if you are seeing a homepage with a plain black or plain white background, you are seeing the problem. If you are seeing a homepage with a background that looks like wood, that is what is called out in the stylesheet.
Many thanks for your help!