screen freezes when on internet and briefly see avast script blocker

Screen has been freezing up lately when on the internet/aol. Everything just shuts down or I have to manually shut it down myself. I also can’t dowVnload files or attach anything to send which stinks since I’m taking an online class! Most of the time I also see a brief screen with AVAST script blocker on it. Any suggestions?

Are you able to try this

Boot time Avast Antivirus Scanning
http://www.digitalred.com/avast-boot-time.php

or start in safe mode and do a virus scan