If you want a checkup follow this guide and attach the logs here(Use the attachments and other options function under
the answer box: https://forum.avast.com/index.php?topic=53253.0

avast! 2014: Scheduling a Boot-time scan http://www.avast.com/en-eu/faq.php?article=AVKB132#artTitle

Important: Please be advised, that the Boot-time scan is an advanced and purposeful feature designed to be used only when there’s something bad going on the system, and usually takes some time before it finishes. That's why it cannot be scheduled to run every time the computer starts, but as needed only.