If you want to know how to prevent avast pop ups, you can follow the step given below:
1. Restart your computer in safe mode.
2. Go to Safe Mode with Networking.
3. destroy all files on your computer which contain the Antivirus file name
4. Then Update your anti-virus software and run a complete scan of your computer.
Hopefully above steps will help you to fix the issue if not you can also follow our blog to see more on disable avast popups.