Scan access denied. Access denied means, generally, that the file is in use by another process (program) and cannot be repaired/cleaned/moved/handled by avast!
You need boot time scanning:
Click on the Menu button.
Choose Schedule Boot Time Scan.
Doing so displays a dialog allowing you to schedule virus scanning.
Check Archives, if you want scan all the archives.
Specify whether all the disks or just a specific folder should be scanned.
Select Advanced options for scheduling details.
Select how to automatically process infected files.
Choose how to automatically process infected system files.
Click the Schedule button to confirm the settings.
Or just run:
C:\Program Files\ALWIL Software\Avast4\sched.exe /A:*