… turning off AVAST is the remedy to speed it up again and avoid “MSIE has stopped unexpectedly and needs to be closed” and other bad things …
What’s wrong with it? not only MSIE affected, but also Chrome, SRWare Iron or K-Meleon …
Btw. totally new installed system withWin8.1 from install DVDs (restore media from manufacturer).
As you used restore media did you uninstall the bundled antivirus ?
… hm … yes I did – probably it must be with the appropriate “hardcore-uninstaller” for the specific anti-virus-software … now I also did – so let’s see if it helped … (I assume it should have) …
… took the hardcore-deinstaller from the antivirussoft-manufacturer … and seems to work … 
Only one resident AV at a time.
You can n ow go back to your first post in this topic and put (Soloved) infron of the topic.
Thanks – the weird thing is that you officially uninstall the preinstalled AV-product and install Avast – and obviously did not uninstall the preinstalled stuff and therefore have more than one AV-product installed …
The only exception to the rule is Microsoft’s Security Essentials. All others require the removal tool provided by the manufacturer. That includes Avast.
thank you … may I ask you to pin that on top of every install instructions? … thank you for doing that … 
It’s part of my signature:
[b]How to Successfully Install Avast http://goo.gl/VLXde[/b]