I doubt that Spybot Search & Destroy is the caused of the corruption but you can verify if Spybot S&D deleted something related with Norton via Spybot S&D recovery tool. See if a related Norton file is there but again, I doubt it is Spybot S&D. Or unless you are using Teatimer of Spybot S&D which will alert users that there is a changes and you mistakenly "allow" Spybot S&D to do not allow the changes and delete it?
I've been running a Spybot scan but it does not corrupt
To reinstall NAV see the following:
Installing Norton AntiVirus 2004 or Norton AntiVirus 2004 Professional Edition that was downloaded from the Symantec Store
nstalling Norton AntiVirus 2003 or Norton AntiVirus 2003 Professional Edition that was downloaded from the Symantec Store
Installing Norton AntiVirus 2000/2001/2002 that was downloaded from the Symantec Store