main() runs again after completion of code

Hello,
I wrote a simple c program in keil to set the voltage on/off for two motors for 10 sec. But when i debug the program, it runs correctly till the end and at the last step of the code it returns to 1st line of main()again, performing all steps again.So the program seems to run for infinite time. Can you suggest me a solution. The same code when i copied and pasted it to another file and ran it on different pc it runs well!!>>?