I have a P4 system with 768MB Ram (it was only 256 earlier, but it was really slow so I added another 512 )

I agree Norton sucks when it comes to removing viruses. Most of the time it is able to detect but not heal/repair it. Maybe I'll uninstall it sometime soon since it expired anyways. I just feel safer since Norton has real-time protection and checks your files..

NOD 32 also has RTM(Real Time Monitoring), Kaspersky also has it, Avast,AVG and Antivir also has it. It is just that we need to explore other options too. No offence, but Norton ought to be thrown out, try meddling with other AVs. You might like a "change of scene". Good Luck.