lost IP address

Hi, I have a NAT internet router. By factory default, IP is 192.168.0.1, and DHCP is enabled.
However, I’ve changed all those settings. I has disabled the DHCP, and disabled the ICMP, and the most serious is that, I forgot what IP address I did change on it. So, I am now having a problem to open the console using browser. There are only 1 WAN port, and 8 Lan ports.
I tried to using sniffer, and it seems that I has discovered the MAC address of it. However, I dont know how I can discover the IP address using the MAC or, is there a way to discover the IP.
PLS help, there is no HARD RESET feature.