That's wrong Technical... I don't even understand how it can even work... He is connected through ADSL connection and he is using hardware router/firewall (I'm also using D-Link DI-604), so that means he doesn't even have to dial to internet. As soon as he logs into Windows, he is ready to open Internet Explorer and browse internet... just like cable connection.
My advice (UPDATE basic) is to set VIRUS DATABASE UPDATES to AUTOMATIC, PROGRAM UPDATES to AUTOMATIC as well...
For (UPDATE connections) - uncheck first one and check the second one... your PC is permanently connected to the internet, because it is like that. Even when you turn off your PC, you'll notice that your ADSL modem and router are still on and doing it's job...
That's how my settings are set and I never had such a problems Manitoban mentioned up there...
Another thing I'm worried about is this...
I scanned from Safe Mode with Ad-aware, X-Cleaner, and ewido. Nothing found. Neither avast nor the backup antivirus find anything.
What is your back-up antivirus and is it working in the same time as avast! ?