I have installed free avast with a 30 day limit. Clicking on “register now” button sends me back to the “you need to register now” page. How do I get out of this deadly embrace?
You have the trial version of one of the pay for versions of avast.
If you want the free avast uninstall what you have now and install : http://www.filehippo.com/download_avast_antivirus/
There have been problems with the servers.
It should work again…!! 
http://forum.avast.com/index.php?topic=65673.msg555052#msg555052
asyn