Hi,
This is a warning message I got from Online Armor saying Avast was doing something “Unusual”
Is this normal or is my computer infected?
It’s normal.
Hm…what activity is it carrying out like this ???
Think it might be for the Boot Scan?
Under the avast! main Settings, Troubleshooting, there is an option:
“Enable raw disk access during avast! boot-time scan”
I believe the default is “on” (checked).
Many security programs use raw data access as I believe it is faster and more efficient at finding malware that could otherwise be hidden by something hooking the windows file system to hide malware.
Yes not unusual. normal practice.
Yeah otherwise it would have been difficult to detect some viruses 
yes it would be hard to detect a virus if AvastSvc was unable to direct access the hard disk. You would have to do malware detections without the help of avast.
Edit - and likely without help of others things as well http://forum.avast.com/index.php?topic=55288.0
Likewise also important to know activity carrying out while this is happening because OA should have AvastSvc set to start automatically. So something may be up. Best to check all activity that occur upon this event just in case something is amiss.