ZEN doesn't run... cannot uninstall, cannot install!

When I tried to open AVG a couple of days ago I received a message "ZEN Cannot start, It's embarrassing…etc" When I checked what to do at the AVG site I was told to uninstall and re-install. So, I uninstalled but when I tried to re-install I got another message claiming that there is a previous version in my machine therefore re-install can't continue. Since then I'm trying everything but can't get anywhere. The online help is not helpful, to add insult to injury, AVG is asking for further payment for someone from their technical site to re-install it remotely!! Absurd…
Can anyone shed a light please?
p.s. I'm running the latest upgraded version of W10 and I have licences to run all AVG products until 2018 - despite that if I try to download a product I'm being asked for further payments…

Hello Orhan,
We regret the inconvenience caused. We would request you  to remove previously installed program traces of (AVG 2015 or AVG 2014)from your system using AVG Remover tool and then try to reinstall AVG Internet Security and AVG PC Tune up.
Note: If you have installed any other conflicting programs like AVAST, NORTON, McAfee or KASPERSKY  try to uninstall it.
Once you have uninstalled from your system,try to follow the steps which mentioned below.
Remover and Download:
1) To download AVG remover tool, please click on this link:  http://aa-download.avg.com/filedir/util/AVG_Remover.exe
2) Run the downloaded file and follow the onscreen instructions.
3) Restart your PC when the restart option is displayed on the remover tool screen.
NOTE: Once you have logged into your PC after the restart, please go to C:\ drive and delete the "AVG REMOVER" folder manually.

To download the AVG Internet Security, please click on this link: http://files-download.avg.com/inst/mp/AVG_Internet_Security_742.exe.
To download the AVG PC Tune up, please click on this link: http://files-download.avg.com/inst/mp/AVG_PCTuneUp_765.exe .
Please feel free to contact us if you need any assistance.
Thank you.