I have be getting a pop-up dialog box saying "Another device on the network is using your computers IP address." I have checked my router's control panel and only see the IP addresses for my computer and the laser printer. I have restarted my router and even change the router's IP address as well as the address range. What is going on here and how can I fix it? BTW - Originally, I manually defined the IP addresses in both devices. However, now I noticed on my iMac that I cannot not specify a different IP address in the System Preferences/Network Panel. Why is that?