Try holding that reset button down for a good 6-8 seconds. I use a toothpick and you should hear a quiet little click when you press it in. The MBL will reboot (LED will change colors) then see if it shows up on your network after it boots back up. If that works, you may also want to try setting up a static IP for the drive and reserving that IP using DHCP reservation on your router.
Otherwise you may have to RMA the drive if it is less than 3 years old.
