PROBLEM SOLVED!!!
I Updated just some “Security Preferences” in the Software Update, NOT the entire OS, and the store now works.
For those who this might help:
1. Open “Software Update.” This takes you to the App Store
IMPORTANT: Do not click the “Update” button. You do not need to update everything and go to a newer, sihttier version of the OS.
2. Now that the App store is open, and you are looking at the software update message, notice a tiny word that says “More” towards the end of the description below the title “Updates are available for your computer.” And I mean tiny, as in 5 pixels high. Click that, it won't install anything.
3. This should take you to a list of things things you can update individually, like “iTunes” or ”HP Printer Drivers.” One of them should be “Security Update” or similar verbage. I have since updated, so that choice is not there for me to show you. Click the “Software Update” choice.
4. You will then be asked to restart your computer.
This fixed my store.
I was running 10.8.5 before I started this, and I am still running 10.8.5.
Hope this helps.