I cannot release the IP address on my MOBO?

I cannot release the IP address on my AOpen MOBO, I have tried resetting the bios, write the eeprom from the bios, installed a PCI Ethernet card, disabled the on-board Lan, and still cannot renew the IP address to connect to my home network. All my other computer work just fine, wired and wireless. The MOBO is 5 years old.