"Avast : the AAVM subsystem found a rpc fault"
Do you have any other antivirus installed in this machine?
RPC is Remote Procedure Call a Windows absolutely necessary service.
The majority of the times, one of the two solutions bellow could be taken:
1. Download the application called Control in my 'signature' bellow.
Run it and follow the window. You have an option 'Change avast! Database storage method' (4th at the list) and choose XML method. Boot.
2. If does not help, Go to Control Panel > Add/Remove programs > avast antivirus > remove and choose the option 'Repair'.
Can you post the results?