Not the first time it’s done this. It’s done this many times before. The only solution was to re-install that and I don’t feel like doing it.
Did you use the cleaner to remove, or are you just uninstalling and reinstalling?
http://www.avast.com/uninstall-utility
If you did use the cleaner and reboot before installing again, can you right click (with GUI closed), and start the service? You right click the Avast Icon in the tool bar.