Trace

Mac:  lsof -i -P | grep -i “listen”

Note down the pid in order to kill it through activity monitor.

The problem: I run WAMP (or XAMMP) but for some reason the apache component could not run (the icon showed some yellowish bar or red bar appear on WAMP icon on the task bar.

Quick checks reveals that port 80, which happens to be used by Apache was blocked by other application.

Some steps that can be done to solve this problem, any one of these steps should work. If not, just choose other options.

1. Shut down Skype. Yes Skype apparently block port 80 (if no other application use it). Click on the WAMP icon and select ‘Refresh all service’. Feel free to run Skype again.
2. CTRL-ALT-DEL, go to process tabs and kill ‘Skype.exe’ process. ‘Refresh all service’ as #1 and reload skype.
3. Slightly harder: go to command prompt, type ‘netstat -ao’ and find ‘:80′ on ‘Local Address’ column. Jot down the PID value of that line. Go to Task Manager –> process tabs –> select view –> select columns –> tick PID –> kill process with the same PID as application that clog port 80 (this is safer than information given by WAMP –> test port 80 as only the really really correct process is killed)

Any other suggestion?