Port 80 is used by System.....

Web Developers could have a lot of problems about developing on localhost, mostly when you have a lot of development tools,such as iis, apache, mysql, mssql, postgresql using the same port.
I had a lot of problems because of it, finally found out how to solve the problem of the used port 80 by the system.

1st: Open a command prompt type it: netstat -o -n -a | findstr 0.0:80
The last column is the process id (PID) of the services witch uses the port. Then start task manager (ctrl+shift+esc) go to processes and click on ,,show processes from all users", and you will find it. (If youd dont have PID column go to->select cloumns and X the process ID).

The biggest problem is when it says its PID 4, witch is in most cases the system.

2nd: In task manager go to services right down: ,,services...". Here you find all the services running, or not on your computer. If you installed visual studio it could install sql server express and some services witch can use port 80. Try to stop them one-by-one and check netstat. If the problem not solved try stopping ,,World Wide Web Publishing Service".

If non of these actions freed up the port, try stopping other processes witch could use that port.

Good Luck!