How do you halt an Arduino program? The only way I know is to remove the power or hold the reset button down.
In ether respect that stops the processor so nothing will blink.
So supply the code and a schematic of what you are making.
Installation and Troubleshooting is for Problems with the Arduino itself NOT your project. It says so in the description of the section. Therefore I have moved your post here. Please be more careful where you post in future.
You may want to read this before you proceed:-
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