The aswDld did seem to work ok, it created a servers.def, however, this file was filled with null bytes…
Something seriously strange is going on here…
I didn’t understand what you meant by this at first, but now i’ve had another look at it it makes sense.
I tried it out, and success! It appears to download!
My issue now is that I have no system tray icons for Avast!, and running regedit still kills the explorer shell.
A full scan of mbam found nothing else.
Can you try to repair your installation?
Go to Control Panel > Add/Remove programs > avast! antivirus > Remove. Then choose Repair function in the popup window (Repair).
Also, check your system time and date and if the avast license is valid.
I’ve tried a full uninstall and reinstall, that didn’t fix it.
I’m currently running the demo license, which is still valid.
The key is valid for 60 days at the first installation.
Only 6 days in the subsequent ones (antipiracy feature).
I suggest you register the Home (free) one and use it if you won’t buy the Pro 
It is still valid regardless, I won’t be registering/buying if I can’t get it working.
Register is free.
Not for pro.
I found the bugger!
It was in Driver32, called yccn.bvu with a key called aux.
I uploaded it to the FTP.
I can email it if anyone wants it.
Do you mean a file that was (infected) blocking the avast update?
Using a boot cd to edit the registry I was able to remove the call to this “driver” which was preventing avast updates and icons from loading amongst other things.
Once I had removed this, and restarted I was able to access things as normal.
This file is not registering as infected, it’s undetected by anything.
Interesting, thanks for the sample.
The virus analysts will do something with it.
Thanks
Vlk
Glad I could help. 
has anything further happened to this?
I’ve had the same problems (redirecting to couponmountain, avast not updating, etc.). following the steps for “No proxy” has worked to get avast to update, but I’m still getting redirected…