Since I installed avast! my computer keeps not responding, I’ll be on the internet and then my window will have the not responding symbol and I can’t use the bottom taskbar and no programs will open or work so I have to manually shut it down. It also happend when I plugged in my iPod and put in a CD. I am using avast! 4.7.1001, XP SP2, Dell Dimension 2400, 1.128 GB RAM, using a dial-up connection, Windows Firewall, and have had no previous antivirus installed. Any help would be great because this is getting very annoying.
Please, check the folder \data\log
Are there any files called unpXXXX there (where XXXX is a random number)?
If so, send them to vlk (at) avast.com
They may contain more information about the problem (maybe a link to this thread).
Vlk explains how to create a dump file here: http://forum.avast.com/index.php?topic=22636.msg187340#msg187340 and here: http://forum.avast.com/index.php?topic=23283.msg193594#msg193594 
There are no unpXXXX files.
So, if it is a freeze, maybe there are info in avast logs, or into Windows Events.
Vlk posted some days ago:
[i]The guidelines for solving of the problem “ashServ.exe using too much CPU” has always been the same:
- Check if the avast tray icon is spinning (while CPU usage is high)
- If it is, click it (wait for the dialog box to open), and check which file is being scanned (the Last Scanned field); the Scanned Count value should be increasing (spinning icon means a scan is in progress)
- Find out which of the providers is scanning the file (click “Details” button and check out the Last Scanned value for each of the providers). The most common providers that may cause this are Standard Shield, P2P Shield and IM Shield.[/i]
I checked any when my cpu usage was at 100%, the Standard Shield was scannning something and the avast! icon was spinning. How do I fix it?
Find out what it was scanning by clicking the avast icon and view the Standard Shield details, Last Scanned as Tech mentioned. This might be flashing past quickly but it might give you an idea of what program is generating the activity that requires scanning.
Or enable the ‘Show detailed info on performed actions’ in the standard shield, see image.
http://img.photobucket.com/albums/v325/for-dwr/ShowDetailedAction.jpg
What is the sensitivity of Standard Shield, Normal is the default ?
It usually happens when I open Internet Explorer. My Standard Shield is set on Normal.
Then check the Web Shield details and there is a ‘Show detailed info on performed actions’ for that too.
When the CPU goes to 100% check Task Manager and see what Process is using the %