PC Won't Recognize Fuze

Thank you.  I’m using Vista Service Pack 1.  The Fuze worked well for about four days; I connected to the PC with no problems and was easily able to copy songs and then listen to them.  Then, after about two days of non-use, I connected the Fuze to the PC and the PC no longer recognized it.  The only change I made to my PC in those two days was that I upgraded Norton Utilities to 2009…but I don’t see what that would have to do with the Fuze.