I haven’t had a complete boot scan for a while because it can’t complete because it stops to ask what to do with infected files it has found. I used to be able to set it so everything was automatically moved to the virus chest. I have searched but can’t find any settings for boot scan. I am using Avast version 5.0.594.
This options (automated) were removed in version 5.0.
They will (probably) be back on version 5.1.
Why was it removed??? I’m sure everyone wants to babysit an 8 hour scan. I guess it’s time to look around for a different virus scanner.
I guess it's time to look around for a different virus scanner.why ? there is no other AV that have a boot scan....... you only use the boot scan if you have a file that the normal scan can not remove bc it is in use......
It has a technical reason (false positives at boot time).
Go ahead… if you find any with boot time scanning 
Completely agree with you tech.
More can be read here:
avast! Blog >> What happened to the automatic actions in the Boot-time scan?