Ok, here is a solution which I found bizarre at least.
as I mentioned in my original post our network is a mix of 32 and 64-bit OS running on the same network.
I could not see the SQL 2012 server (64 bit OS) until I shut down the firewall on the Server OS. Just opening ports on Server side did not do a thing to improve situation. Is this a bug on OS or a firewall? - I do not know.
So currently I am using AV firewall capability on the server as well as general network firewalls but not windows firewall on the server.
Thanks all of you who tried to help.