I cannot operate my windows 8 system when the scan is taking place and the scan is taking longer and longer to complete, around 25 minutes...is this normal?

Janet, Have a look @ this article (https://support.avg.com/SupportArticleView?urlname=What-are-AVG-system-requirements-and-supported-opearting-systems). If it's a problem why not schedule your scan for when you are not actively using your system.
AVG Guru

Janet, Have a look @ this article (https://support.avg.com/SupportArticleView?urlname=What-are-AVG-system-requirements-and-supported-opearting-systems). If it's a problem why not schedule your scan for when you are not actively using your system.
AVG Guru

Hi janet,
In order to analyze it please provide us with diagnostic output (gather it right after inducing issue) using this tool and please add detailed description of issue.
Thanks