nt server dhcp problems

Work in school with about 35 w98 clients and nt 4 server, recently had broadband installed so I had to change the IP address on the server as requested by broadband company then set up new dhcp scope for clients. Server reboots with new ip but cannot release and renew ip addresses on clients. (I had logged them all on ready.) Activated and reactiveted scope, changed ip back to orginal it all works but when you change it back to new settings clients can't see server, I gave one client a static address from the new range (an excluded number) and it logs on sweet as a nut - so I'm thinking dhcp problem. Also when I do IPconfig on server it gives 2 nic addresses for one mac address why?Any help would be appreciated!

 

Begining is the best solution!! hehe! So, You should do your DHCP as a new one, anyway, you were given a new IP, so it's absolutely new, isn't it!
Try mine!
Seperate DHCP from network, simply unplug the connector!
Stop DNS, delete your DHCP scope.
Uninstall, yes, uninstall you NIC!
NEXT! Do it in reverse!
Reinstall you NIC by restarting Windows! type cmd in Run command and ipconfig /all. How many NIC you have now? ( ofcourse, after you set the static IP, subnet...)
Restart DNS.
Create new DHCP scope, activevate,... ( Be sure you do it completely right).
Now, renew until DHCP work, ( Until you see the green light, you knew it).
Now, test DHCP in client by plug the connector!
Try this first!