Hi,
During the boot scan Avast send me this message:
C:\....... error 3221225506
what does it mean?
I think Eddy is right. The access denied problem with 4.1 version is due to the executables are on avast folder. In version 4.5 it will be on Windows folder. So, in some systems, access rights won't be a problem anymore. Official release of 4.5 is expected for tomorrow.