Problem : When I start the PC, there´s a red circle on avast! a-ball icon in system tray and when I click on it, the error message appears saying "the AAVM subsystem detected a RPC error" and it's impossible to start any software. My PC is frozen. Impossible to work. I must wait 4 to 5 minutes before the red circle disepear and allows me to work.
This is a tipical RPC error.
RPC error is generally related to other antivirus present or, at least, firewall blocking. Do you use a firewall? Which one?
Anyway, RPC error is most likely correct by this procedure:
Go to Control Panel > Add/Remove programs > avast! antivirus > Remove
Then choose Repair function in the pop up window (Repair).
Take a look into Administrative Tools > Services
and see how the three avast services are set to start (automatically or manual).