You don't say or attach an image if these popups, so it is pretty hard to say why or what is causing them.
You also don't say what Avast program or version number of the Avast program you have installed, nor do you give the Operating System its being used on ?
All these could help us to help you. Since you posted in the General sub-forum there is no clue there either.
There is nothing to stop you uninstalling avast, but not knowing what Operating System you are using, that would have to await an answer.
