No IP address

My Raspberry Pi 3 with DAC was working fine until last week. Then the IP address was no longer active. I first tested the network connection, no problem there (plugged my laptop into the ethernet cable that ran to the Pi to test) . I thought maybe the Pi 3 add died and replaced it with a new one. Still not getting an IP address. I then downloaded and burned the May2Play image to a new SD card. Still no IP, so I cannot connect to the Pi and Max2Play. So network connection works, new Pi3, new SD card, but nothing works. I am a loss to think of anything else that could be causing this problems. Any ideas where to go from here???