I have just bought new laptop with Windows 8 pre-installed. Having been delighted with the free avast on my previous PC, I bought the Pro version for the new one. Shortly after installation, some of the Windows8 Apps (Skype, Store, photos etc) stopped working (they opened by hung on the "loading" screen. I wasn't sure if it was avast that had caused this but uninstalled it anyway and the apps came back to life. I sent a message to avast support via their website two weeks ago and have not even received an automated "thanks, we'll get round to it sometime" response. Until I hear something positive, I think I will just depend on Defender to ward of the evils of the internet.