Concept is to allow computer technician insure payment for work done. The Tech will install a hidden program on customers computer. At set time widows, this hidden software will check a server. The hidden software will perform a "task" based on a setting on the server. "Tasks" can be as simple as displaying a message on the computer showing how much is owed. Or perform a task, such as turning off the system, encrypting user data. Once customer pays, the tech makes a change on the server for that select customer to undo negative issues. The server side should be WEB accessible. Server side maintains the customer list and list of "tasks" that can be done.
Think of it like a remote engine kill for car rental places. The ability to 'disable" a non paying customers computer to insure payment for services rendered.
1. client side hidden software that checks a central server on a scheduled times. adjustable times.
2. Server tells hidden client software what to do, based on owners input. Example, Nothing, display a message, turn off system, encrypt data, decrypt data.
3. client softer performs task per server side request.