A program executing apparatus for executing a software program, comprising:
- reception means for receiving a program start enable signal distributed from a data distributing device and data for substitution or insertion for original data of said software program;
- and
- control means for substituting or inserting the original data of said software program for said data responsive to the program start enable signal received by said reception means for executing said software program,
- wherein the start enable signal comprises time information, and wherein execution of the software program is not started or is interrupted if the time information sent at a given time is smaller in value than time information sent prior to said given time.