Firstly you are in the wrong forum, this is for the Server version of avast! Hopefully one of the Moderators will move it to the correct avast! 4 Home/Pro forum.
Yes there are two round icons, an ' i ' and an ' a ' icon (when you eventually get them back) you can merge the two, right click the ' i ' and select 'Merge with main avast! icon.'
avast! icon missing - Check the option in the Appearance tab of Program Settings.
What other security based software do you have that might block new startup entries, e.g. Spybot S&D (TeaTimer), AdAware (AdWatch), SpySweeper, Spyware Doctor (StartUpGuard), PrevX, WinPatrol, ProcessGuard, etc. ?
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).