possible problem with iMac

I have an iMac 9.1 that I suspect might be infected with something. I posted this initially in the networking forum but they suggested I go here. I am posting this from a WIN 7 machine; my iMac has been removed from the network per suggestion. I would like to know if there is a problem with my iMac, and if so, how to correct it. I have noticed an issue with my router logs and I don't know what is going on. Perhaps someone here can help. I have a iMac 9.1 connected to a Netear WNR3500 router via an ethernet cable. I noticed my router log file contains DOS attack: STORM entries that seem to indicate the attack is originating from my iMac. Note the logfile below: [Admin login] from source 192.168.1.5, Thursday, Sep 02,2010 13:23:44 [Admin login] from source 192.168.1.5, Thursday, Sep 02,2010 13:01:13 [DOS attack: STORM] attack packets in last 20 sec from ip [192.168.1.5], Thursday, Sep 02,2010 12:39:30 [DOS attack: STORM] attack packets in last 20 sec from ip [192.168.1.5], Thursday, Sep 02,2010 12:39:05 [DOS attack: STORM] attack packets in last 20 sec from ip [192.168.1.5], Thursday, Sep 02,2010 12:38:3 [Admin login] from source 192.168.1.5, Thursday, Sep 02,2010 10:43:12 [Admin login] from source 192.168.1.5, Thursday, Sep 02,2010 10:05:26 192.168.1.5 is my iMac. I notice that these attacks, or whatever they are, seem to come in bursts about 3-5 at a time and these occur about 3-5 times a day. I have no problem accessing the net. I have no idea what these are, or even if they are a problem. I have VirusBarrier X5 and NetBarrier X5, and a scan showed no problem. However, when I first setup the mac (a little over a year ago) I didn't enable the trojan horse and spyware stuff on NetBarrier, but they are now.

Mods please lock this. There has been progress in the other thread and I no longer need to pursue this here. thanks.

Thanks for posting back and letting us know Peace be with you