Cannot open Control Panel - update

In this post http://www.windowsbbs.com/showthread.php?t=52688&highlight=control+panel
it was suggested to check 3rd party shell extension. I ran XP_Shell and outside of Google there are no other apps running besides MS.

I did have several popup blockers running and I deleted all of them (uninstalled) - turned off windows firewall and to the best of my knowledge I only have Norton runnig for AV and Popup blocking. I have disabled Norton as well and I still cannot get Control Panel to load.

When I try to run CP, the screen flashes, about half the app icons in the tray disappear and I am returned to the desktop.

How can I be sure there are no more AV or popup programs running?

Thanks. -Bob