You can write simple windows service to monitor your task. But what if your machine is down?
You can go a step further and integrate with AlertGrid service.
Each time your program executes some logic it should send signal to AlertGrid. Than you can set up rule like 'if my program hasn't responded for more than 5 minutes -> send Email/SMS'.
There are some examples in various programming languages how to do this, so you don't need to be a seasoned coder.
This assumes that you have access to your source code, if not you can use AlertGrid Basic monitor which will send list of available processes to AlertGrid and if your program is not on a processes list then you might get email alert.
AlertGrid's Free account is enough for this case.
PS: I am a developer in AlertGrid team. We would be glad to help you in case of any questions.
Hope that helps!