Boot scan

right click the “a” ball, click start avast antivirus
click menu, select schedule boot time scan
select the path ie the drive you want to scan.

Make sure system restore is off. Restart your computor.

Yes, all restore points will be removed. Files in system restore are protected and can’t be removed with system restore enabled. System restore is a double edged sword. It protects/saves certain system, even those infected. If you don’t disable it, infections will keep reoccuring from the infected files.

After you are sure you are clean, re-enable system restore and if you want create a resore point.