Trojan causing IP address to be locked to same IP address when going online

Three days ago I received a Trojan Virus that Norton Internet Security caught and eliminated.  Norton stated that no further action is required and quarantined the virus.

 

The next day, when reviewing my Security History I noticed that I had received messages every 3-6 minutes that "Unused Port Blocking Has Blocked Communications.  Inbound TCP connection from 218.10.111.19 local service" Then the port number was listed.

 

I Used IPligence to trace the address and it came from Beijing China.

 

I called Norton and they indicated that it was the firewall doing it's job.  (However, every 3-6 minutes is a lot In my opinion).  They referred me back to my ISP. I told them that each time I come online I have the same IP address.

 

I called my ISP explained that my IP won't change and has been the same for a couple of days.  They indicated that it should change each time I do a modem reset. I spend a couple of hours attempting to force a modem reset using instructions the ISP provided when I was on the phone with them.  No luck.  We also checked to insure that IP address generation was set on automatic.

 

Late last night I was able to get the IP to change, however within a few seconds it returned to the old IP address.

 

My questions are:  Has any one had this problem or seen this problem following a Trojan?

 

Does anyone know of a solution?

 

I should state that I have run Norton virus scans several times and have also run the Norton Super Eraser from the Norton  Website and nothing finds a virus present.  Meanwhile my IP address is locked and the remote address continues to attack every 3-6 minutes.