Need Help Quick if possible I'm onsite! Way to watch network traffic with Windows?

[BS911]

I'm having network issues at a courthouse that has 50 or so computers on its LAN. Something is flooding the network but I don't know without going to every single PC. I know viruses like Welchia can cripple a network and I know if I had linux I could scan and watch what IP is trying to access which port (like 135).

Is there anyway I can do this through Windows with a 3rd party application or do I have to use Linux or a Network Packet Sniffer?

Thanks!

-BS911