Avast gadget contains buttons to open Avast user interface, launch Scan and Update actions. This gadget is useful, but takes a little ten more seconds to load windows as by default this gadget configured to run at startup.
You can uninstall Avast Gadget by
Right clicking on the desktop click Select “Gadgets”, select and right click on Avast Gadget aka “Avast Antivirus monitor gadget” and select Uninstall.
Once you uninstalled this gadget you may not able to bring it back, so make sure and remove it only if it’s not useful for you.