I have tried to set the resident protection to the “standard” setting by sliding the bar to where it says standard but when I reopen it it always says “disabled” Can’t find anything in the “Help” regarding a problem like this.
Anyone have an answer???
See if the avast icon is in the lower right corner of your desktop. If it is not, right click the desktop icon and click the “pin to start menu” and restart you computer. I swapped hard drives yesterday and this got mine working again. Good luck.
Which avast are you using? (free/pro/ais) Which OS do you use?
You can try to reinstall from scratch.
First use this: http://www.avast.com/uninstall-utility
Download the latest build here: http://forum.avast.com/index.php?topic=58183.0
Install & enjoy… 
asyn