I have been experiencing IE8 problems due to the Norton Internet Prevention add-on.
Running Norton Security Suite Ver 126.96.36.199 (Comcast) on Win 7 32 bit and IE8.
The Internet Prevention add-on (188.8.131.52) prevents iexplore.exe process instances from closing when the browser is closed. Multiple browser windows/tabs results in multiple process instances remaining running. This results in IE8 becoming unresponsive, and either not opening new windrow/tabs, or conversely not closing currently open windows/tabs.
Disabling the Norton Internet Prevention add-on in Internet Explorer resolves all problems and restores normal operation of IE8.
I just wasted time with "Live Chat", wherein Analyst Santhosh suggested running Live Update, and/or removing the product and reinstalling from the Comcast website. Of course, these recommendations failed to resolve the problem, which is clearly a conflict between the Norton Internet Prevention add-on and Internet Explorer (and I am guessing that this affects all versions of IE and all versions of Windows)..
I had originally posted this to an existing thread in the Norton Internet Security/Antivirus forum, but a poster remarked that the Comcast Norton Security Suite is addressed here; hence the "move"..