Nortons causing problems with XP PRO

I am finding that on multiple computers, that as soon as I install any of the Symantec (Notrons) products, that user files are becoming corrupted so that users cannot log into their computers. This usually ends up with re-installing Windows. Another symptom is on boot-up, the machines won’t boot into the OS, just a black screen. You have to start the machine using the “last known good config.” This will eventually continue to the point that the user won’t be able to log on.