Trying to uninstall AVG

I have tried all ways suggested to un install avg. I have also downloaded avg clear and when i double click this i get a message saying I cannot access this file. Also AVG keeps a pop up coming telling me i have threat with avgclear

Hi Graham,

We're glad to look into this & help you.
Please let us know the operating system of your computer in which you're experiencing the issue.
Also, share us the screenshot of the message that you receive while attempting to run AVG Clear & let us know the reason to uninstall AVG.