"Mega Antivirus Test"
The above was a convincing study; "...The amazing thing is that Kaspersky Online Scan is my new champion - it found more than any other, including any of the desktop antivirus programs! ... However, the bad thing is that it only scans; it doesn't allow you to remove the viruses it found.
...and the best 'installed AV' was ..."AntiVir PersonalEdition Classic 6 found the most viruses..." (also FREE)
I use Norton (Kaspersky's OnLine finds no problems) mainly due to the other Norton Software;
WinFax Pro
GoBack
CleanSweep
Partition Magic
*what will Norton buy next...*
I did ditch a paid copy of Norton Personal Firewall just because ZoneAlarm (FREE) worked so much better.
Norton's renewal comes due in a few months...
I am sure that some of the other (than NAV) stuff like GoBack also really slow a fast system.
It's just that (unlike Win System Restore, now disabled), it ALWAYS WORKS and Norton has to take credit for no format/reinstalls for me.