DHCP has wrong default gateway

I have a Win98 machine that seems to lose it’s DHCP information every time it is restarted.The computer then has no Internet access and TCP/IP applications will not work. Winipcfg shows a valid IP address, subnet mask, and a current lease. However, the default gateway is set to the IP address of the local adapter, not the router. None of the other stations on the subnet have any problems. The Win98 machines are running TCP/IP, IPX/SPX, and NetBEUI protocols for different applications. Removing the extra protocols does not fix the problem, nor has removing and reinstalling the NIC. Does anybody know why the default gateway would set to the NIC address, or how to fix this?