Just been told by NTL to uninstall avast version 4.7 as it has stopped me accessing the Web via my cable modem!
It has worked perfectly well up to this date.
Is this due to the new version being installed?
And the reason they gave for uninstalling avast was ?
What was their anti-virus solution after uninstalling your AV ?
Did this happen directly after you updated to 4.7 ?
What is your firewall ?
Does it allow internet access for ashWebSv.exe, if so delete the entry and then connect to the internet your firewall should ask permission again.
Thank you for your reply. 
I turned Avast protection off.
I then tried accessing a website and it was found.
I then turned Avast protection back on and have had no more problems so far…
The only thing I can detect is that my speed seems a bit slow for a 2mb broadband connection.
My firewall is on Windows XP sp2.
I’m not sure how to check for ashWebSv.exe?
I did not uninstall Avast as I did not think it was blocking my internet connection.
You should have only need to pause or terminate the Web Shield provider not avast as you would be totally unprotected.
I’m on dial-up and I notice no difference, but for broadband you may notice it a bit more as it is downloading more quickly effectively giving the web shield less time to scan the content. However, it shouldn’t be that great and it is hard to quantify broadband speeds as even with a 2MB theoretical connection there is no guarantee that you will get those speeds (contention, etc.). No ISP that I know (UK) will guarantee those speeds without your paying considerably more for your service.
The windows firewall as it doesn’t provide full outbound protection, you need a third party firewall to do that. All you can do with the XP firewall is have exceptions (programs specifically allowed), from the Windows Control Panel, double click the Windows Firewall. When the window appears, select the Exceptions Tab, here you should either see ashWebSv.exe listed, if not select Add and navigate to the C:\Program Files\Alwil Software\Avast4\ashWebSv.exe.
avast doesn’t block it isn’t a firewall it monitors web (http) traffic and alerts if a virus is found, but not blocks, that is usually the firewall task.
Zone Alarm free http://www.zonelabs.com works fine with avast and has a reasonably friendly user interface. There are others, Comodo, Jetico, Sunbelt Kerio, etc.
See some firewall tests for comparison, some are freeware but many are paid for versions http://www.firewallleaktester.com/tests.php.