i want window application used by many logged in user remotely(Example)

You could write the application once and use Terminal Services to provide the application to many users but only install it on one machine. or you could write a client server architecture for your app and each client would connect to the server.

Am I right in asuming that your reference to DNS server is you want to run the application on a server that Runs DNS on your network?

You need to be far more clear about what you are trying to acheive and not ask people to write the app for you, May be detail what the application is for and provide some code you already have.

Don't ask this again. The answer is the same. What do you think a 'dns server' is ? It's a server for providing domain names against IP addresses on the internet. This has nothing to do with what you want. Again, if your users all log in to the machine, and control it remotely, you just need to store each users information in an area local to the user, so they don't collide. That is all.