Finding Windows applications/softwares to monitor changes to a directory on remote computers

Hello everyone, I would like to find some Windows applications/softwares to monitor changes to a directory on remote computers, which consist of:

1. A client program that runs on the machines to be monitored.
2. A server program that runs on the monitoring machine.

* Detailed description:

1. Client program: connects to and exchanges information with the server.
2. Server program:

• Manages the list of clients. 
• Selects which client to monitor and selects the directory on the client machine to monitor. All changes to this directory (deleting/adding subdirectories, deleting/adding/modifying the contents of files within the directory) must be reported to the user (on the server). 
• Must be able to monitor multiple clients simultaneously (each client monitors only one directory). 
• Graphical user interface. 

Thank you very much.