Those free AV's are "ok" for your child's PC that does little more than play games, screw around with IM or surf the net, but they lack many features that full-blown retail AV's offer. And if you ever get hacked or a really nasty virus, you'll wish you'd had a decent AV and FW on your system. . .believe me.
"Someone". . .refer back to the larger thread on this. There are TWO ways to skin this cat. I've done both.
Apparently the old CD key gen is the more problematic and rigorous way and requires you to not have had Norton AntiVirus 2005 on your system in the past such as the Trial-Ware. In any event, -God's- "patch" worked like a charm for me with both my 98se and Win2000 OS's.