hi
when i try to enter my activation key .i ca only enter the first letter ,the second letter will not enter.then i can enter the numbers ,but cannot enter the next letter.copy and paste will not work.i have uninstalled the programme and then downloaded again a new programme .and tried to register the activation code again ,but got the same result .what do you think is the problem.thanks. ???
em,
Try entering your activation code this way:
Right click on the “A ball” in the tray.
Then, click on About Avast.
When this window opens, 
click on License Key.
Enter your code here and click OK.
This should take care of it.