PDF Files changed to AVG HTML

I've just taken the steps above and the unwanted PDF HTML files all reverted to Adobe PDF files again.  Trouble is that they will no longer open.  When I click on them I get: Windows cannot find… Make sure you typed the name correctly, and then try again.  However, if I select 'open with' and 'AVG Secure Browser then they open as HTML files.  Trouble is, I've got to share these files with students and they don't have AVG.   How am I supposed to get out of this mess?  When I try to uninstall AVG's browser, I get a messgae saying I don't have access.  This is very annoying for me as I am trying to get some lesson prep done!  I can't do it!  

Hello Ignatius,

We request you to check whether AVG Secure browser is installed on your PC.
Please right click on any one of the PDF file that was changed HTML and select "properties".
Click on "Change" and select the "Adobe reader" application and click Ok.
All the files that was changed should revert back to PDF files and should open via Adobe reader.
Keep us informed about the status.

Can you tell me how to convert it back to PDF Files ? 
changed all of them by once not 1 - 1
i already ready Alok kumar suggestion but i can't find the pdf there's only adobe acrobat reader pc, is it same ?
Thank You

Check if the AVG is up to date and restart the PC.
This issue has been fixed in the recent update.
Keep us posted.

Hello Ignatius,

We request you to check whether AVG Secure browser is installed on your PC.
Please right click on any one of the PDF file that was changed HTML and select "properties".
Click on "Change" and select the "Adobe reader" application and click Ok.
All the files that was changed should revert back to PDF files and should open via Adobe reader.
Keep us informed about the status.