I upgraded to 7.0 and my license disappeared even though it is valiid for at least another year. Also, I changed ISP providers and my old e-mail address (Larryg@persona.ca) is no longer valid and I can not register to post a ticket. Please help as I feel very vulnerable. Thank you…
You could try contacting sales(AT)avast(DOT)com and try explaining the situation to see if they can A) track down your existing license and B) you somehow confirm legit ownership of said license.
Check your old emails (you do keep backups) looking for the email sent to you with your license. If you purchased through the avast web site then the payment would have been handled through Digital River (Element 5) so I would assume it would come from that source. That should have stuff like order reference, etc.