How can i make a NT server 4.0 clone

Hi everyone,

I have WINDOWS NT 4.0 SERVER and 20 workstation connected to it. There is one common program everyone uses and the main file is stored on SERVER. Whenever server is down no one can do their work. Their work is depended on server. I want to have one more server of WINDOWS NT 4.0 so that if there is any problem with server then i can use the other one and i want both the servers to be on network and whenever any one updates data it should be updated on both the servers.

CAN ANY ONE HELP ME ON THIS PLZ………

Regards….