WHEN I choose to activate it gives me a message of 'this file contains a virus and was deleted'....
what program give that message?

sounds like you may have a infection that is blocking AV install … maybe a rogue security program

follow instructions and attach logs (not copy and paste) http://forum.avast.com/index.php?topic=53253.0

run in order listed (if problems running tools, try from safe mode)
AdwCleaner / Malwarebytes / OTL / aswMBR

when done, removal experts will be notified and help you
when finish, all tools used will be removed