as far as the workgroup:

right click my computer, select properties, under computer name, domain, and workgroup select change settings. When the system properties pops up, click the "change" button on the Computer Name tab. Change the workgroup/domain. click ok, restart computer.

don't know what you mean by configure IP's. but if it is what I am thinking of. You need to go into network and sharing center then click on manage network connections and from there you can go into each network device.