DHCP settings keep getting setup

Im having touble with by Ad Hoc wireless connection. I have a system running
Vista and I am using ICS. I am sharing the Internet connection with the
wireless connection. As a result, the wireless connection will disable DHCP.
When I set this up all works fine. I reboot the system and it does not work
any longer. The DHCP on the wireless is enabled again. I cannot connect. I
go in and manually disable DHCP and all works fine again.