Hi Arvind, I think it should not ask for username/password Phil Newlan has got some good step by step guide on RAC installation on Windows. I think it is also mentioned here "RAC Assurance Support Team: RAC Starter Kit (Windows) Doc ID: 811271.1" The OS user you use for the installation must be the following: "Run the installation as the local Administrator account, The local admin username and password must be the same on both nodes. If you must use a domain account, then you must ensure that the domain user is explicitly declared as a member of the local Administrators (not granted membership to this group through another group) on each node in the cluster." -- Karl Arao karlarao.wordpress.com karlarao.tiddlyspot.com