Not necessarily no. If you've installed new sound software or drivers, Norton AV is known to often not like them very much. I had this exact problem when I installed drivers for my Creative Audigy ZS soundcard.
What I recommend doing is uninstalling Norton Antivirus completely, going to
http://www.symantec.com/symnrt and downloaded the SymNRT tool (this only applies if you're using the 2005 version, another tool from the same page can be used for earlier versions). Running the tool (to get rid of all traces of the program) and then re-installing it afresh.
Also, when installing it, I recommend clean booting your PC (which means loading it up with as few programs as possible) just for installing it, so as to help prevent any conflicts whilst it installs. You can do this by clicking Start > Run > typing "msconfig" without quotes > Under "Selective Startup" uncheck Startup Items and use the Services tab to uncheck all non-Microsoft services. Then reboot. To return the boot process to normal, simply do the same again but check the "Normal Startup" box.