AVG Secure browser

This program installed itself. It has converted all my PDF files to 'AVG HTML' files which I cannot read.
Happily I back up everything, but I'm not happy ans my computer is now unstable in its operation. I have removed AVG antivirus and the AVG secure browser (an interesting claim!). I have ised AVG for at least 25 years and was pleased with it - but not now.
Is there any way I can reverse this problem?

Hello Richard,

We regret for the inconvenience caused.

We will work together to sort this issue. You don't have to uninstall AVG AntiVirus from your computer. This might have happened due to AVG Secure Browser settings. Please right click on any PDF file on your computer and select "Open With", change the default program to any PDF reader and that should solve the problem.

Click on this link https://support.avg.com/SupportArticleView?urlname=Download-and-install-AVG-AntiVirus-Free to install the latest version of AVG AntiVirus free.

If you face any difficulties, please let us know and we will assist you further.