NIS 2012 & Utilities has "Disappeared"

Hi,

Yesterday I Installed Norton Internet Security 2012 on my partners Laptop and my own.  I also installed Utilities on mine.  All went OK, and I ran a Full scan and installed all updates,  but last night I was online and going to run a scan after having been online for some time, but whilst the Norton icon was on the desktop, nothing ran, nothing appeared on screen.  Also utilities icon had disappeared from the desktop.  It's as if Norton has uninstalled.  Help!  By the way, I use Firefox as my browser, my partner uses Windows explorer and hers is still OK.  I am not at home right now, so any advice I'll try tonight.  Thank you