Hello!

I am new here and I was wondering if someone could give me some help.
I have Norten Internet security 2003 running on windows XP and recently when I took a look at my Norten Internet Security log file, I noticed this whenever I boot up:

-Rule "Block Windows File Sharing" blocked communication. Local address: Forensics(169.254.240.228)(netbios-ssn(139))
Process name is "System"

I never noticed this message before and that is definitely not my IP address.
I also noticed that my computer would automatically shut down for no reason whatsoever whenever I'm on the internet. It has happened about 3 times in the last 2 weeks or so, most recently today.

I scanned my entire computer with Norton antivirus today but it found nothing.
Can anyone help explain what's going on? Should I be alarmed by this?

I've also been getting a lot of these message popping up on my Norton Internet Security:

-Rule "Default Block Microsoft Windows 2000 SMB" stealthed (203.198.103.164,microsoft-ds(445))
Inbound TCP connection
Local address,service is (0.0.0.0,microsoft-ds(445))
Remote address,service is (203.198.103.164,32801)
Process name is "System"

Whenever that occurred, I would just copy the IP address and put them under the "restricted" section with Norton Firewall which prevents any type of communication with that IP address and my computer.
But it's been happening a lot lately. Should I be alarmed?

I'd appreciate any help!