Try a clean install…

Download and save avast clear
Download and save RejZor’s cleanup tool You will need to scroll down the page to find it.
Download and save your choice…
Free
Pro
AIS
Premier

Run the “avast clear” from above. You will be prompted to reboot into safe mode…click “yes”.
Reboot and run RejZor’s cleanup tool from above. (This will remove any low level drivers left behind from “avast clear”.)
Reboot.
Install avast choice from above.
Reboot and register or insert license.

edit: typo