Mountain,
Please uninstall Bitdefender, run the AVG Clear tool to remove AVG traces completely and then try to install AVG free again.
Download and run AVG Clear tool: https://share.avg.com/steam/PSP/AVG2017/AVG_Clear.exe. This tool will help with removing AVG 2017 and its traces.
Open tool
User Account control - click "Yes"
Windows safe mode - click "Yes".
Choose installed version (AVG Free, AVG Internet Security)
Click "Uninstall"
Click "Restart computer".
After the PC is booted back to normal mode, please try to install AVG. Please, feel free to let us know if you require any further assistance.
Hello Mountain,
We are sorry to know that. Could you please check if you have any other AVG program or other security program preinstalled in your computer. Please run this AVG remover tool and then initiate the installation of AVG.
Thank you
I've installed clean installation of Windows 7, and it doesn't let me install AVG Free (See the screen shot).
It also doesn't let me to install AVAST Free.
I've installed the Windows on freshly made partition so I don't have the idea how could be a virus if it is one.
I've ran Malwarebytes and the result was no viruses.
Yes, and it works normaly.
This is the machine I'm sending you reply from, so the internet definently works. 
Maybe it's something with router settings or similar, because I've tried to install windows 10 on the same machine and the problem was the same.
Anyway, I've installed Bitdefender in the mean time.
I have the same problem, and I did everything you said, but it still doesnt work. What should I do.
Hello Narek,
I am sorry to hear that. Please send us the screenshot(http://avgclick.me/getscreenshot) of the error message you receive when you try to install AVG. And let us know the version of Windows installed in your computer.
Yes, and it works normaly.
This is the machine I'm sending you reply from, so the internet definently works.
Maybe it's something with router settings or similar, because I've tried to install windows 10 on the same machine and the problem was the same.
Anyway, I've installed Bitdefender in the mean time.
Mountain. Have you definitely checked out your internet connection?.
AVG Guru
@ Narek Hayrapetyan
Narek, For your info, just in case that you are unaware, you can post the screenshot here in your topic. Click on 'Answer' & then click on the 'Image' [mountain symbol] & follow the instructions.
AVG Guru
I have the same problem, and I did everything you said, but it still doesnt work. What should I do.
Mountain,
Please uninstall Bitdefender, run the AVG Clear tool to remove AVG traces completely and then try to install AVG free again.
Download and run AVG Clear tool: https://share.avg.com/steam/PSP/AVG2017/AVG_Clear.exe. This tool will help with removing AVG 2017 and its traces.
Open tool
User Account control - click "Yes"
Windows safe mode - click "Yes".
Choose installed version (AVG Free, AVG Internet Security)
Click "Uninstall"
Click "Restart computer".
After the PC is booted back to normal mode, please try to install AVG. Please, feel free to let us know if you require any further assistance.