Are you using Windows XP/Vista?
Can you schedule a boot-time scanning?
Start avast! > Right click the skin > Schedule a boot-time scanning.
Select for scanning archives.
Boot.
If infected files are found, it's safer to send them to Chest instead of deleting them.
This way you can further analysis them.
See also:
http://www.digitalred.com/avast-boot-time.phpOr just run:
C:\Program Files\ALWIL Software\Avast4\sched.exe /A:*
Access denied means, generally, that the file is in use by another process (program) and cannot be repaired/cleaned/moved/handled by avast!
The report file is created automatically in <avast4>\Data\Report\aswBoot.txt