How to display an alert message to all network users locally?

Hi all,
I don’t know exactly where to post this thread. Opolize if it is not the correct place to post it.

I have a software that is for our Organisation s/w, which is running in a network locally. This network systems are all build with the Thin clients and having the IP address for each one. In this, i have userid and password to login and perform the operations regarding the user levels.

Now

  1. I want to send an alert type message to all logged in users, that will be displayed on all the users monitors at a time and stay for 30 sec on the screen, without any installation of the third-party softwares in each system except the admin system.

  2. I want to check the login status of the specific user, if that user is in login state, call that user with voice message telling that “attend the Admin/section/chairman room immidiatly”. This voice message will be sent to that specific user system only based on the IP address. For this one also i dont want to install any s/w in the network systems but allow to install in Admin system.

Please provide the help,guidelines and solution to this problem.

Thanking you…

How to