Hi diannder,
The Norton Perfomance Monitoring feature doesn't actually do anything except tell you when an application is using more system resources than normal. So the problem is only being reported by Norton, not caused by Norton. It's not that Norton doesn't recognize the amount of installed RAM - it is simply reporting that something is using a higher than normal percentage of the available memory.
These alerts can usually be ignored, since it is normal for programs to occasionally demand extra resources. However, when you say you get freezes when going online it may be that your browser is having difficulty with a page that is loading a lot of active content such as Flash. Norton should be telling you which application is hoarding the memory so that you can troubleshoot that application - which is what the Performance Monitoring function is intended to do.
You can turn off Performance Monitoring or adjust its thresholds, but all that will do is curtail the alerts - it will have no effect on whatever is actually causing the computer to hang.
