If you have REG_DWORD named EnableDHCP set to 1, then they probably don't exist (or have an effect) if a DHCP server is provided. Other addresses include SubnetMask and DefaultGateway. It is possible to set a static address, and the address will be stored in one of those keys. Under there are keys related to interfaces. IPv6 looks like it uses a key called Tcpip6 in the middle of that, instead of just Tcpip. You did right by looking at the 'HKLM\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\Interfaces' key, for IPv4.
