Installing AVG anti virus

Hello Joan,
I am sorry to hear this. Please remove AVG Traces completely using AVG Clear tool and AVG Remover tool using below instructions:
1. Use the link https://share.avg.com/steam/PSP/AVG2017/AVG_Clear.exe to run the AVG Clear tool.
2. Open the AVG Clear tool, click Yes in the User Account control dialog.
3. Click No in the Windows safe mode dialog.
4. Select the installed version of AVG and also check the box 'Uninstall AVG Zen'. Then click Uninstall, and Restart computer.
5. To run AVG remover tool please follow this link: http://avgread.me/1DEtNP0 .
To reinstall AVG Internet Security unlimited, please use this article http://avgread.me/1FKGRZI .
If the issue persists, please share the screenshot to provide better assistance.
To create a screenshot, please use this link http://avgread.me/1aZxsAV .
Thank you.

I have downloaded the anti virus software but cannot install it.  The computer goes through the motions untill 97% is installed then it comes up with an error.

Joan, If applicable… 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

Hello Joan,
I am sorry to hear this. Please remove AVG Traces completely using AVG Clear tool and AVG Remover tool using below instructions:
1. Use the link https://share.avg.com/steam/PSP/AVG2017/AVG_Clear.exe to run the AVG Clear tool.
2. Open the AVG Clear tool, click Yes in the User Account control dialog.
3. Click No in the Windows safe mode dialog.
4. Select the installed version of AVG and also check the box 'Uninstall AVG Zen'. Then click Uninstall, and Restart computer.
5. To run AVG remover tool please follow this link: http://avgread.me/1DEtNP0 .
To reinstall AVG Internet Security unlimited, please use this article http://avgread.me/1FKGRZI .
If the issue persists, please share the screenshot to provide better assistance.
To create a screenshot, please use this link http://avgread.me/1aZxsAV .
Thank you.