http://technet.microsoft.com/en-us/library/cc709667(v=ws.10).aspx
If Online Armor telling that avast wanna configure BCD, then we must assume that this action is legitimate. But such action can easily be malicious as well.

Do you wish to check that? FRST shall resolved the mystery. Or you/we can clean temp files. All files in %temp% should be safe to remove. This CMD commands shall attempt to clean files from %temp% folder:

CMD (aka command prompt) > type:

DEL %TEMP%\*.* /F /S /Q

Enter and then type …

CMD: RD /S /Q %TEMP%

Enter …