Browser TOO SLOW with Toolbar

Firefox 15.01 with the Norton Toolbar which came with NIS v20.1.1.2 is much, much too slow.  Login to community dot norton dot com covered more than 1 minute from click on the stored login item to being at the loaded page logged in.  Browsing to other sites is also slower than normal. 

 

System: laptop with Windows XP sp3, Firefox v15.01, NIS v20.1.1.2, Celeron 2.0 GHz, 512 MB RAM; wireless internet connection.  Firefox on system has search bar, bookmarks toolbar, and norton toolbar, and none else.