IP reservation is the process of assigning a specific IP address to a device, such as a computer, so it receives the same address each time it (re)connects to the network, such as when you restart it ...

You could try running "lsof -i :80" as root. That should provide some useful process info. You can always "man lsof" for more information. Also, Apache won't be able to bind to port 80 if it isn't run ...