I used to use Avast on my old PC but I haven’t installed it on my new one and just use defender. What do I have AvLaunch in the task manager on startup?
If you have not installed Avast on your new machine, why do you think Avast is launching.
A screenshot of Task Manager would be good for us to see what you are seeing.
Have you checked your C: Programs Files and Program data. Folder to see if any Avast entries.
Also some new PC’s/Laptops come with Avast pre-installed