System Preferences will not stick


I have been using 10.1 since release. Love it. Wednesday I had a problem with Mail when some how one of the mail boxes got locked. I finally unlocked it in the finder and it is fine. But I also made the mistake of installing the new Netscape and when I tried to install it as the default in Systems preferences it would not take. I uninstalled and tried to select both IE and Old Netscape and still no luck. And the default setting is missing. Any ideas?