For those of you who have an anti-virus/security program/suite installed on your system, it is important to remove those programs prior to installing NSS. It is recommended that the programs first be removed via Control Panel > Add/Remove Programs. Once the program is removed, do a search for a Removal Tool for that program. Many programs have removal tools available and insure a more thorough removal of the old program and a better chance of a clean install of NSS.
Here is a suggested link to assist with the removal:
Turn off all your remaining anti-malware tools (except Windows Firewall) and reboot.
The Norton Security Suite,is available only for Comcast High Speed Internet customers. You can go to the “Get Comcast Norton” page http://constantguard.comcast.net/norton?cid=NET_33_601 and confirm each of the prerequisites listed there and the minimum system requirements on subsequent pages.
You may be required to logon with a Comcast.net Identifier that you use for Comcast Email or for this Forum before you download.
Please follow the instructions for installation and view the video for more clarification.
Once installation is complete, open NSS and manually Run LiveUpdate (located on drop-down under PC Security left side of main page of NSS) as many times as necessary for it to respond "no more updates available". If a reboot is requested, reboot and then continue to Run LiveUpdate until it responds "no more updates available" and then reboot one last time. Your installation should now be up to date definition wise and ready for use.