Why do I keep getting the message Avast will expire soon?? What do I have to do? It never shows me how to extend it. any help is appreciated.
what version of avast do you have ?
support for avast 4.X will end this year
Avast! Free Antivirus 5.0.677 http://filehippo.com/download_avast_antivirus/
how to register, recomend to use the online with no key, only name and a valid email address
http://support.avast.com/index.php?_m=knowledgebase&_a=viewarticle&kbarticleid=459#idt_01
Welcome to the forums, lori121 
What Avast is trying to tell you with those pop-ups is that one day soon, v4.8 will no longer be supported and that will happen very soon. So, you should not wait because, the end for v4.8 may be tomorrow, or next Monday, or on Dec 27th, or … the real end is not known but it will certainly occur very soon.
Avast does not want you to be using v4.8 when the end of support comes as you will then be using out of date definitions and will not be well protected. Avast wants you to update to v5.0 so that you will continue to be well protected. Please follow the advice of the pop-ups as well as the advice above.