AVG Zen didn't work, now Internet Security won't

I have completely uninstalled all AVG programs from my computer several times: first using the standard uninstaller, then (after the problem persisted after reinstallation) using the AVG removal tool, then later using the standard uninstaller followed by forcing the AVG removal tool to run despite it not detecting anything, and after that going and deleting the many folders and registry keys that were left behind even after all this. 
I should point out that as far as the AVG removal tool is concerned, I do not have AVG protection installed. AVG protection shows up under Programs and Features, and the local AVG Zen says it is installed, but AVG Zens from other computers on the network report no Internet Security installed. But if I run the removal tool and tell it to scan for AVG programs, the only thing it detects is AVG PC Tuneup. Also, when I go to AVG Zen Menu and click About AVG, it lists the PC Tuneup version, the Framework version, and the Setup version, but it does not list Protection or Internet security.
I have downloaded the file from the link you provided, as well as used the file that I originally installed AVG Ultimate with (that resulted with Internet Security working just fine, but a malfunctioning AVG Zen), and even an offline AVG Protection installer. In each case I end up with a free version of Protection. 
Also, at some point in the past few days when I reinstalled everything, AVG Zen changed appearance. It stopped resembling the AVG Zen on my other two computers and now uses a slightly different menu and lacks the Refresh option.
I have no other security programs installed on the computer experiencing the problem.
I also want to point out that my subscription being listed on the My AVG Account is a recent development that took place a month or so ago after I contacted tech support. Before that, my subscription worked, but it was not listed on the AVG website.
Now my subscription IS listed under My Account, but this computer for some reason thinks that I do not have a full subscription.

I have completely uninstalled all AVG programs from my computer several times: first using the standard uninstaller, then (after the problem persisted after reinstallation) using the AVG removal tool, then later using the standard uninstaller followed by forcing the AVG removal tool to run despite it not detecting anything, and after that going and deleting the many folders and registry keys that were left behind even after all this. 
I should point out that as far as the AVG removal tool is concerned, I do not have AVG protection installed. AVG protection shows up under Programs and Features, and the local AVG Zen says it is installed, but AVG Zens from other computers on the network report no Internet Security installed. But if I run the removal tool and tell it to scan for AVG programs, the only thing it detects is AVG PC Tuneup. Also, when I go to AVG Zen Menu and click About AVG, it lists the PC Tuneup version, the Framework version, and the Setup version, but it does not list Protection or Internet security.
I have downloaded the file from the link you provided, as well as used the file that I originally installed AVG Ultimate with (that resulted with Internet Security working just fine, but a malfunctioning AVG Zen), and even an offline AVG Protection installer. In each case I end up with a free version of Protection. 
Also, at some point in the past few days when I reinstalled everything, AVG Zen changed appearance. It stopped resembling the AVG Zen on my other two computers and now uses a slightly different menu and lacks the Refresh option.
I have no other security programs installed on the computer experiencing the problem.
I also want to point out that my subscription being listed on the My AVG Account is a recent development that took place a month or so ago after I contacted tech support. Before that, my subscription worked, but it was not listed on the AVG website.
Now my subscription IS listed under My Account, but this computer for some reason thinks that I do not have a full subscription.

Chris,
Appreciate your efforts and patience so far to resolve the issue. We have sent you an email instruction to get connected with our technical support team. Please follow those instructions to get in touch with them and you should be able to resolve your issue. Thank you.

Hello Chris,
We are sorry for the inconvenience caused. We see from your record that you have active subscription of AVG Ultimate. We suggest you to completely remove all the old traces of AVG completely from your computer and install the latest version from this link http://files-download.avg.com/inst/mp/AVG_Ultimate_761.exe. Also, please make sure that there is no other security program installed in your computer. If there is any, please remove the same as they may conflict with the latest version of AVG.
Thank you

Here is the short version: I have AVG Ultimate. AVG Zen was the only component not working, so I reinstalled everything, and now it works but Internet Security doesn't. The story, however, is a great deal more complicated than that.

I bought AVG Ultimate via 3rd party retailer several months ago after my previous AVG Ultimate subscription lapsed. This led to a horrible transition time on all my machines where AVG constantly downgraded or uninstalled and reinstalled things. Eventually my Windows 8.1 laptop was able to run the most recent version of Internet Security and PC Tuneup with no problems. However, the AVG Zen menu/interface did not work at all - I could use my desktop link to control PC Tuneup, and Internet Security ran automatically just fine, but my ability to tell it what to do was extremely limited. Whatever problem causing it, none of the standard solutions worked so I let that go up until I had enough time to fix it.

A few days ago I ran a full system scan via Internet Security, then uninstalled AVG completely. I reinstalled it through a fresh installer from AVG's website. The installation took abnormally long, but eventually it claimed to have installed successfully. AVG Zen worked fine, PC Protection worked fine.

When I clicked on Internet Security through AVG Zen's menu, however, I got an error message about a module, so I rebooted. After rebooting, AVG Zen's menu no longer listed Internet Security, but the free Protection. This made no sense because I was logged into my AVG Ultimate account and PC Tuneup/Performance was running the pro version. So I uninstalled free Protection, rebooted, and tried to (re)install Internet Security.

With 1.9 gigs free on my C drive, I got a message from the installer saying I needed 90 more megabytes of free space. So I cleaned things up until I got 2.15 free gigs, rebooted, and tried to reinstall it again. It claimed success, and I had a little over 1.9 gigs free when it finished. (My C drive's free space fluctuates from 1.5 to 3 gigs depending on its mood and the phases of Jupiter, but AVG certainly did not use up 2 gigs for installation). Once again the installation took abnormally long.

But when I went to use it, the menu looked weird. It looked like Protection, no Internet security, and according to my AVG Zen monitor on my desktop, my laptop was NOT running Internet Security. AVG Zen on my laptop, however, claims it is installed and working fine. I reboot again to see if this helps.

Following the reboot, AVG Internet Protection's menu no longer loads at all. It just opens a menu that says "loading" and stays that way.

Mind you, I have been running AVG Ultimate on this thing for 3-4 years, ever since I bought it, so unless the requires have changed in the last WEEK, it should be able to handle it. I really need to get internet protection working against because it's a laptop I'll be using on public wi-fi in a few hours (I am a student and I use it for class), and I can only try uninstalling and reinstalling so many times.

Hello Chris,
We are sorry for the inconvenience caused. We see from your record that you have active subscription of AVG Ultimate. We suggest you to completely remove all the old traces of AVG completely from your computer and install the latest version from this link http://files-download.avg.com/inst/mp/AVG_Ultimate_761.exe. Also, please make sure that there is no other security program installed in your computer. If there is any, please remove the same as they may conflict with the latest version of AVG.
Thank you