Here's what worked for me after everything else failed. I didn't attempt repair/update install though. This is much simpler.
Stop the sidebar.exe process. Use regedit and delete this key: [HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Zones\].
Restart sidebar process.
Have no idea why it works but it does. Found it on another forum. I applied this fix several days ago and system has been running fine.
