The issue with the icons is likely to recur if the cause wasn't avast.
Have (or did) you have another AV installed in this system, if so what and how did you get rid of it ?
As a temporary measure you can create a desktop shortcut for this file C:\Program Files\Alwil Software\Avast4\ashDisp.exe (the avast icon and interface to the providers). Right click on the file and select Send To, Desktop (create shortcut).
What other security based software do you have that might block new startup entries, e.g. Spybot S&D (TeaTimer), AdAware (AdWatch), PrevX, WinPatrol, ProcessGuard, etc. ?