Program to be built - exe file

We need a program to run at customized times of the day that freezes the PC screen for customized lengths of time and shows at customized message with our company branding.

Here Are A Few Further Details;
- The program will run on PC's with Windows 7 or XP
- The program will need to ping up a message 15 minuets before the set time which can be cancelled off
- The program will need to ping up a message 5 minuets before the set time which can be cancelled off
- At the set time the program will need to freeze the screen for an hour and can only be bypassed with n admin password
- The Admin user will need to have a Portal showing who has their screens blocked