Yes there is, it is the Simple User Interface (SUI), accessed by:
a) right click the avast 'a' icon, select Start avast! Antivirus, a memory scan is done first before the SUI is displayed.
b) there is normally an avast icon on the desktop that you can double click that also starts it.
c) or directly via explorer, C:\Program Files\Alwil Software\Avast4\ashSimpl.exe.
Check out the avast help file, Simple User Interface section for more information.