What is this icon on my address bar?

The icon currently has a #1 attached to the target. I click on it, nothing happens? Thanks for looking.

If your referring to the round one with the zero on it, it is Avast. Avast is security software which by the way is the only one I use. Works great. Mine is yellow. Yours looks greyed out according the image you attached. Open it in your programs and check to ensure its enabled.

Thanks copiman. It is Avast. The same icon is in my tray and that is yellow. I will ask my brother why it appears with a # next to it up near my menu bar.