How can I block ports?

I have a virus scanner telling me a port is open and I have some type of trojan. I scan the entire HD and "nothing" was found. I visited the virus scan website and it only tells me how to view open/listening ports, but not how to close it.

I do not want to take any risks and I rather just close that port specially if I'm not using it.

I already did a search for port 1434 and honestly, I do not need it open. What can I do to close it, block it, disable it? - Ouh, if it helps the OS is Vista Ultimate - Let me know if you need any other info!

Thanks in advance...

re: How can I block ports?

Try going into the firewall on Vista. there should be a port tab where you can make exceptions or add ports. Go there.