I think you are wrong! Have you ever used norton in a P4 pc which has not a good configuration!
If not then check it that after installing norton are u able to do some work in that pc!
I think NORTON is most bad, I can tell u some viruses which are not detected by norton "lax.exe","avg,vbs" etc.
And kaspersky is so difficult to use and for me it has never crashed a pc even it is a P3!