The avast skin on the simple user interface is used when you want to run on-demand scans, it doesn't need to be on the desktop, you select it from the avast status bar 'a' icon, right click, select Start avast! Antivirus.
The VRDB Virus Recovery DataBase, is used by avast to repair some infected files (namely .exe) you have to run it to get the benefit of the repair option. See the avast help file, Healing, VRDB for more information.