My avast pro 5 is not running. The program doesn’t recognize the license file (.avastlic) as a valid file. All the modules are out of reach. The program doesn’t restart. My license is valid to 2011/12/26. What’s happening? How can I work on this?
Welcome to the forums, Paulo 
First, try a repair if avast and then see if it will recognize the file.
To do a repair of avast :
Control panel > Add/remove programs > click once on avast to select it > click on Change/Remove > scroll down the left pane and click on repair > click OK> follow directions