Hi porchp, welcome to the forum
Does your avast! user interface look like the image?
If so, you have disabled skins, please follow these instructions to get them back:
right click avast! tray icon --> program settings --> 'Common' tab --> check 'Enable skins for Simple User interface'
(if you have the user interface open, you will need to close it and then re-open it.)
-Scott-
EDIT: Missed a step in instructions...