1. Does the behavior persist if you start IE in No Add-ons mode? To start
IE in No Add-ons mode:
=> Right-click on the blue IE desktop icon and select Start without
Add-ons; or
=> Start | (All) Programs | Accessories | System Tools | Internet
Explorer (No add-ons).
Troubleshooting and Internet Explorer's (No Add-ons) Mode:
http://blogs.msdn.com/ie/archive/2006/07/25/678113.aspx
2. Does the behavior persist if you Reset IE Advanced settings (RIES)?
http://support.microsoft.com/kb/923737 <= Read before using!
3. What anti-virus application or security suite is installed, is your
subscription current, and is it supported in IE8? What anti-spyware
applications (other than Defender)? What third-party firewall (if any)?
Were any of these applications running in the background when you installed
IE8 (if it's not a Win7 computer)?
4. Has a(nother) Norton or McAfee application ever been installed on this
machine (e.g., a free-trial version that came preinstalled when you bought
it)?