ok...have you updated the Firmware?
try 1.13 first
Set logging to Firewall and Critical only
turn off the Advanced DNS
make sure the WAN and LAN address settings are different. as in if wan address is a 192.168.1.x change the LAN to 192.168.77.x
save, reboot and try it again. Make sure you've hard booted the dsl/cable modem from a full power off and disconnected state as well.
post what you get.