Cannot find which application uses port with netstat

Question

netstat -o -n -a | findstr 0.0:80

gives me a PID of 4 but in my vista task manager I can't see any process with such PID.

Why?

Answer 1

It's possible the process is running as a different user, click show processes from all users:

You can also use netstat -b which will show you an executable name as well as a PID:

Proto  Local Address          Foreign Address        State           PID
TCP    john:1038              localhost:1039         ESTABLISHED     1400
[firefox.exe]

Answer 2

Make sure you have clicked "Show processes from all users" in the bottom left hand corner.

Failing this, take a look at Microsoft / Sysinternals Process Explorer which is basically an enhanced free task manager.