Norton Antivirus 2009 slows startup

Hi Guys 

 

We have a domain controller running Windows Small Business Server 2008 and most of our users are running Windows Vista Ultimate and a few are running Windows XP Professional all machines have Norton Antivirus 2009 16.5.0.134 running on it. The XP users have no problems on their machines but the Vista users experience problems when they start up their machines while connected to the domain. It takes about 30 minutes for the windows to startup.

 

If the network cable is not plugged in Windows starts up without any problems.

I have used the removal tool and reinstalled NAV and the problem still persists.

If NAV is uninstalled Windows starts up without any problems.

 

Has anyone come across this problem.