You can install adblock-plus and spell checker in firefox rendering mode. Go to Tools->Mozilla firefox->add-ons and search those extensions.
Please provide the following information before reporting problems: Avant Version; System(also point out it is a 32 or 64-bit OS);IE; Memory Size; CPU Speed; Optional: Firewall; Graphics Card For the problems hard to replay, could you add me into your MSN or Skype list if you use either of them? The advantage is that you can let us know the situation in the first place by making some screenshots, sharing your screen or explaining the specific problems more clearly when they happen. E-mail: Jasmine#avantbrowser.com(please repalce # with @) MSN: dishmoon#msn.com Skype: JasmineThunder