system
12
Sorry for this interruption, but…
Why the need to use registry cleaners for Avast old (un)installations?
Clean your web browser’s cache and download the latest stable Avast setup from Avast’s official website (if it works) or from http://www.filehippo.com (for example).
Try http://www.avast.com/uninstall-utility instructions (maybe better under Windows Safe Mode), and use the new setup just downloaded to reinstall anew. Reboot between EACH step, including after the latest Avast installation finishes.