I get a pop up which says “Your License Key is not Entered”. I have Avast4Home on my computer. I use Windows XP Pro. I have a License Key. But I don’t know how to enter it. The key was entered and the program was working. I don’t know how the key became “not entered”. How do I re-enter my license key? Thanks to anyone who can help. ??? aa26668@comcast.net
Right click on the a icon in the taskbar by the clock… and click “About avast!”
There will be a button that says “Licence Key”… Left click that button and enter your key… 
The license key for the updates expires on the home version after 14 months. Could that be the case here? If so you need to obtain a new (free) key from the website.
My license key was issued on 03/05/2004. But thanks anyway, I wasn’t aware of the 14-month limitation.
As for the Avast icon on the task bar, there is none. It was there but recently, for unknow reasons, disappeared.
Absent any other suggestions, I believe I will have to uninstall the program (37.54 MB) and re-install via download.
Have you already tried a repair of Avast?
control panel > software > add/remove > Avast > repair/change
Did you follow this?
No Technical, he didn’t try it… he said he doesn’t have avast! blue icon in the system tray.
aa26668 - have you tried simplest solution ever ?
Right click your START button (Windows) Go to PROPERTIES. Choose TASKBAR tab, and clear the checkmark on HIDE INACTIVE ICONS at the bottom of that window. Now, your avast! blue-ball-icon should reappear in the system tray (close to the system clock). If that doesn’t help, then try Eddy’s advice… uninstall avast! and then reinstall it from the scratch.
Cheers !