To the question of the firewall pings...

Sometimes it's a legit "attack". Sometimes it's the ISP "pinging" to make sure it's an active connection. Sometimes it's a website sending a check to make sure you're you. It's all up in the air.

Tracing does no good in 99.99999999% of the cases - any hacker worth his/her salt will just be spoofing the IP address anyway, and all you'll come up with is either (best case) no result or (worst case) an innocent IP address. And, as noted above, a lot of hits are generated from abroad in the first place.

Just keep the firewall up and updated (they're constantly coming up with new countermeasures, and the hackers then try to counter them, and the cycle continues - sometimes I think it's all made up by programmers to keep themselves employed), and keep a virus scan up and updated as well. Trojan Horses are called that for a reason - no matter how 'advanced' the firewall, loading something in that opens the gates for the "enemy" will go around it.

M