What is blocking port 80?

I am trying to run Apache @ port 80 on Vista Ultimate, and it won't
start. When I run a netstat -ab, I get the follow:
----------------------------------------------
Active Connections

Proto Local Address Foreign Address State
TCP 0.0.0.0:80 Dungeon:0 LISTENING

Can not obtain ownership information
TCP 0.0.0.0:135 Dungeon:0 LISTENING
RpcSs
[svchost.exe]
TCP 0.0.0.0:445 Dungeon:0 LISTENING

Can not obtain ownership information
TCP 0.0.0.0:554 Dungeon:0 LISTENING
----------------------------------------------
What is this IP of 0.0.0.0? A week or so back Apache was running fine
on port 80.

You say that a "week or so back Apache was running fine". So what did you do
in the past week? It is likely that it will save a lot of time if you can
answer that.

Also, it will help if you can specify what firewall you are using.

Does Apache have a way to provide error messages? Did you check there? Did
you look at the Windows event logs to see if there are relevant messages
there?

Run NETSTAT -ano and write down the PID number.
From a task manager you can see what process is having the PID.
Ex, Skype is running on port 80.

Yes, this is normally my approach to debugging my code, but I cannot
think of anything that has changed.


At present I have Windows Firewall on, but this happens when I have it
turned off, too.


Yes, but nothing useful:

(OS 10013) An attempt was made to access a socket in a way forbidden
by its access permissions. : make_sock: could not bind to address
0.0.0.0:80

Ah, I like that set of options, very useful! It turns out the PID is
4, which is System. I am thinking this is a Microsoft change.

Figured it out, I turned off SQL Server Reporting Service (SSRS) and
SQL Server Integration Server (SSIS) and port 80 is now free! Thank
you for the help!