The exact same thing happened to me! After extensive online research, I discovered that there is a thread on the Microsoft.com social forums regarding the "not genuine" issue and G Data antivirus. I understand G Data uses Avast technology. I can't help but wonder if the issue extends beyond G Data; ie is it the Avast components of G Data that are the cause?
I found a workaround to get my Windows 7 "re-activated", but it was a royal pain in the behind. Had I known that restoring the two items in my Avast chest might have fixed the issue, I could have saved hours of work and research. I have to tell you, getting strong-armed to buy a new license (in my case close to $400 with Ultimate 64 bit) after paying for my OS was not pleasant. They already have a monopoly, does Microsoft really have to over-build their anti-piracy measures to the point that legitimate users have to face this kind of thing???
The G Data issue thread is here:http://social.microsoft.com/Forums/en-US/genuinewindows7/thread/8e047dc1-ddfc-47a6-a40a-e60a84817d92
Is there any connection to the G Data problem and Avast 5.0??? If anybody DOES have an answer to this, please let the rest of us know. I think Avast is a great product, but if it causes Windows 7 and Vista to de-activate, then Avast needs to fix this problem post-haste.