Hi Littlebear. I was mistaken, if Webrep is installed, it will be in the Avast interface under Additional Protection. Sorry about that. From there you can install it to any of your web browsers. Once you install it to the browser you can enable or disable it from there like any other extension or add-on, or you can uninstall it. You can also uninstall it from the Avast interface. Uninstalling won't completely remove WebRep from Avast, only the browser, but you can completely remove it if you want to from your computer's Control Panel.
If you try again and WebRep doesn't install, I'd just install it from the Control Panel. If you do, you'll need to be connected to the internet and will have to restart when it's done.