Norton 2009 stops working when browsing

I've used Norton 2009 for about six months with no problems until the past few days. When I first boot up the computer, I will browse a few mintues and then get a notice that is somthing like "symantec service has stopped working." When I try to open Norton, it will not open. I have to reboot the computer and then all seems normal. I use Windows 7 and Firefox 3.6.3. I regularly run Live Update, so I know everything is up to date.

 

I tried the one click support and it showed all products normal. Anyone else have this problem?

 

Thanks.