How do I get my Windows Server 2008 machine to obtain an APIPA?

I have to two Windows Server 2008 computers connected to an isolated network (a cisco 2950 switch connects both computers). However they do not get an APIPA (eg. 169.254.x.x). Instead the computers get preferred addresses beginning with 192.168.x.x. Same thing when computers are connected via a hub. These address are leased so they must be comming from a DHCP service somewhere, but I can's pin it down. I have not added any DHCP server roles yet, so what device is issuing these address and how do I disable the service?