If you need to perform a packet capture under Windows without having to install Wireshark, here are some netsh commands:

netsh trace start capture=yes tracefile=c:\net.etl persistent=yes maxsize=4096 filemode=circular overwrite=yes report=no

When you are done with your capture do:

netsh trace stop

This will take some time.

You will see the files under C:\net.etl and net.cab