The IP address of your computer can be set from the command prompt by running the following commands at an administrative level prompt:
netsh interface ip set address name="Local Area Connection" static 123.123.123.123 255.255.255.0 123.123.123.1 1
Local Area Connection is the name of the adapter you want to modify. In single NIC systems it is normally called Local Area Connection.
123.123.123.123 is the IP address you want to set.
255.255.255.0 is the subnet mask.
123.123.123.1 is the gateway.
1 is the gateway metric. You can leave this as 1 for almost all cases.
If you want to enable DHCP you can run:
netsh interface ip set address name="Local Area Connection" dhcp
There are two commands for DNS since administrators typically configure a primary and secondary DNS server.
For the primary DNS run:
netsh interface ip set dns name="Local Area Connection" static 208.67.222.222
For the secondary run:
netsh interface ip add dns name="Local Area Connection" 208.67.220.220 index=2
If you want to configure the computer to use DNS from DHCP run:
netsh interface ip set dnsservers name="Local Area Connection" source=dhcp
When you are finished with all of your IP and DNS changes run ipconfig -all to review the new settings.