Hi Syed, you just need to install w2k3 (advanced/enterprize edition) on the new hardware, install clustering service, configure clustering, install E2k3 on the new hardware (it will install exchange's cluster aware services) and that's it. If you already have messages on your exchange, restore it from backup. Before you conect the new hardware to your net, reset the account of your old exchange in AD (computer account). Good luck!