My Avast (4.1.418) is taking along time to scan and not scanning archive files. What's up?
Could be a lot of thing...
What are you running beside avast scanning?
Perhaps you need to post a list of your running proccess but it won't be easy to 'solve' this, as I think, could be a lot of things...
I suggest you run the scan where you are away from the computer or, at least, on the screen saver module.
Now I realise you started two identical threads...
http://forum.avast.com/index.php?board=1;action=display;threadid=5569