Technical warning: this may make your eyes glaze over unless you're a techie type. :-)

Every once in a while I have to learn something I didn't expect to learn, but which, upon its accomplishment, makes me feel very pleased that I was able to find out about something so useful and share it with others who might be having the same problem.

I was installing WAMP today, which basically turns my computer into a server that is then able to process websites under development. This gives me the ability to try out coding on a test server without disturbing a live site. This is something I've been wanting to do for a while, and now with all new sites being created in Content Management Systems it's become pretty much a necessity. Plus, I want to be able to write some code for various reasons and this way I can test it without having to be online. Much more convenient.

Despite following all instructions I  found, I could not get WAMP to work for me. I went to the forums and looked for solutions, finding a list of things to check. I went through that list and amde sure I did everything suggested, but was still not having any luck. The key to Wamp's functioning correctly had to be use of port 80, it was the only thing left. I needed to use port 80 for WAMP, and something had to be blocking it. I had closed down all the programs I had running that it was suggested I close down, but the problem was still the same. I needed a way to find out what was running on port 80.

My research on the web paid off, and I finally discovered how to find out what's using what port on my computer. It involved a Windows utility named "netstat".

Here's how to find out what's using port 80 (or any other port) in Windows XP:
1) Go to START-->Run and type cmd to bring up a Command prompt

2) In the Command Prompt window. type netstat -aon.
This will bring up a list of the ports and list what's listening, established, starting, closing and all other states on them. In this example, look for the one ending in :80 (yes there's a colon between the IP address and the port, so it may look something like 127.0.0.0:80).

3)To the right of the IP address ending in :80, you should see that the port is "listening", and to the right of the listening state, there's a PID (Process Identifier) number. Make a note of that number.

4) Open up the Windows Task Manager (CTRL-ALT-DEL). In order to see the PID numbers of the various processes so you can identify which process is using Port 80, click on the Processes tab, then choose View-->Select Columns from the menu. Check the box next to PID (Process Identifier). You'll now be able to see which process matches up with the PID number you noted earlier. If you used fport, you'll already know which program it is.

Once I'd identified the process using port 80, I was able to close it down and save myself a lot of effort, and found I did not have to shut down my antivirus and other programs at all. And it saved me a lot of time trying to figure out what was causing the issue.