Avast Scan At Boot
Avast antivirus comes with several default scans. Quick scan - Scan of your computer's system volume (usually C: drive).
Only files with extensions such as 'exe', 'com', 'bat' etc. Only the beginning and at the end of the file, where viruses are normally found, are tested.
Full System Scan - A more detailed scan of all your computer's hard disks. All files are scanned according to their content. The whole file is tested.
Avast Boot Scan Log Location
Removable Media Scan - Scan any removable media (e.g. USB flash drives, external hard drives) when attached to your computer. Select folder to scan - Scan only a specific folder or multiple folders. Boot-time scan - Perform a scan at bootup to detect and remove viruses which cannot be detected after start up. Click on Schedule Now to automatically scan the next time your system is restarted.