When you use the DHCP service, the DNS server and default gateway settings randomly change from the client's values to the servers IP address?
DHCP clients may receive leases from Window 2000 computers that are NOT running a DHCP server?
If you ever has ICS configured on any computer and removed the NIC without disabling ICS, you will experience these problems. When the ICS service attemps to start, it causes the DHCP allocator for ICS to offer leases.
To fix the problem:
1. Start / Programs / Administrative Tools / Services.
2. Scroll to Internet Connection Sharing.
3. Right-click ICS and press Properties.
4. Set Startup Type to Disabled.
5. Stop the service.
6. Press OK and exit the Services MMC.
NOTE: You can use NETSVC and SC to perform these tasks remotely.