Unable to extract content from downoaded file AVG Tune Up

Can anyone help. I have purchased AVG Tune Up and have downloaded the file but when I click on RUN I receive an on screen message saying unable to Extract Content from file. Contact system administrator. I am the only person who uses this PC and am the administrator. 
How do I extract and install the file content please help!

Regards - Allan H

Allan, Have you followed fully this AVG article (http://avgclick.me/installAVGPCTuneUp)?.
AVG Guru

Hi Alan

Just went through the instructions you sent on the link  I have downloaded the file(again) but when I click on Run I continue to get the same message ' Inable to extract setup content ********** contact system administrator'  - Very frustrating - I am a silver surfer and not very technically minded.  I thought it would be easy but sadly its not.  Thinking of cancelling.   I already have AVG Internet Security 2015 running on this PC.

Allan, Have you followed fully this AVG article (http://avgclick.me/installAVGPCTuneUp)?.
AVG Guru