I have a new state-of-the-art computer (a Alienware Aurora R4 ALX 64 bit windows 7 system). I just installed the latest version 9.0.2018 of Avast (free version) and enabled the addon in IE 11. When I use google to search and attempt to create a new tab entry that tab entry hangs or IE crashes. If I disable the Avast addon then I have no problems.
Have you rebooted the system since installing avast? also make sure that the “Enable Enhanced Protected Mode” is unchecked.
What is the TAB entry you are adding ?
Since it is a new system, did you remove the pre-installed av before installing avast?
Eddy Alienware systems at this level are custom built so no AV would be installed.
Eddy Alienware systems at this level are custom built so no AV would be installed.
If it is the Dell version, they do offer an option to select an AV solution during the custom configuration process. So, it is possible a previous AV solution has expired and the OP is looking to try something else. In addition, I know for a fact this rig was available for at least a year because there is a youtube video of someone unboxing that exact model on 04/05/2013.
Of course it’s a DELL version… DELL make Alienware 
How long the system has been available is not of any concern since the OP has stated it is “new”
No matter if it is custom build or how long it already is available, it doesn’t mean that there isn’t/wasn’t another av installed.
True
This computer had no previous antivirus software on it. I rebooted the system after installing Avast.
Craigb, where do I uncheck “Enable Enhanced Protected Mode”?
The new tab I am talking about is at the top where the existing tabs are and you click on the area to the right of the right most tab. That creates a new tab page.
See below attached picture:
New tab in IE red box? Is that what is crashing?
It’s in the internet options via the tools icon at the top right of the browser or internet options in control panel.
It should be unticked by default and left that way if using avast Browser Protection ( AOS )
When I use google to search and attempt to create a new tab entry that tab entry hangs or IE crashes. If I disable the Avast addon then I have no problems.
mchain, yes that new tab or if a new Internet Explorer window is created it crashes,
Craigb, where do I uncheck "Enable Enhanced Protected Mode"?
CraigB, that check box was never checked.
Workaround then would be to disable and remove the AOS add-on in IE11. AOS does work in Google Chrome or Firefox without issues afaik, so you could try either to see if you get the protection you desire by switching browsers. Please consider use of Sandboxie in your browser for even more protection, see sig below, if you really want to stick with IE11.
If your AOS issue is relatively new, I’d check to see if the latest IE Microsoft security fix has something to do with it?