Intrusion started even right after Windows starts (offline)

Guys, I have a weird experience, I hope you could help me with it.

I’m using dial-up broadband connection and already activated my router’s firewall. Now, lately, when I boot up Windows XP (SP3), sometimes COMODO Main Windows (summary) popped up, and when I see the network defense, it says the firewall has blocked xx intrusion attempt(s). The number XX is increasing starting from 1 and just keep going.

The intrusions seemed coming from “System”, “Windows Operating System”, “C:\Windows\system32\svchost.exe” with various source IP, port, and destination IP.

I don’t know what should I do…