I updated my avast program from being a free issue to a $40 subscription and the license key that they gave me in my email doesn’t allow me to update it. How can I get protected with the avast program!!!
Left click on the icon of Avast! in your TaskBar. Scroll up to Update and do the two thing that its say. If you need any help to configure it ask us or a expert of Avast!. But i think the Pro Version configuration default should be great 
So if you want more infomration wait a guy to reply to your post.
See the tutorial: http://www.avast.com/files/tutorials/insert_key.htm
Please take a look here: http://www.avast.com/eng/faq-invalid-license-number.html
What is the error message?
Is your system date/time correct?
Do you use copy & paste method?
Are you sure you do not include the ‘last blank space’ in the paragraph while copying & pasting?