Desktop Software Development

I need an application that runs on startup and Displays a message I type from a remote computer in my control panel. It will be deployed on all PCs in my company, running Windows 10 Pro, and every morning I want to write a message on my PC. When the employees reach their desk and turn their computer on they will see my message. It will be the same message for all. I need a simple report to tell me the name of the computer and how many seconds it was open before the user will click X and close the window.