I have to shut down Norton 360 as it is slowing my desktop down dramatically, what could be the problem. Of note too is that FIrefox is doing the same thing!
If you feel Firefox is also causing the issue, even if you have disabled Norton, it does not seem to be a Norton issue. Was your system running fine.
Is there, or was there, any other security program installed on this system? If so, you need to fully remove it using the removal utility for that software. Even a trial version that comes with a new computer can cause confilicts.
When did this start happening? Was there an update to some software or the OS that might have coincided with the slowdown.