Question: I have a C# program that I want to run automatically every night without me having to do this,

I believe there is a way of doing this by setting an automated task however im not sure how to do this?

P.S. not sure if this helps but it has a .exe file in its library.

Thanks in advance.

Answer: 
What about registering this as a scheduled task?

Go to Control Panel -> Scheduled tasks.

Here you can easily add your exe as a task and choose when and how often to run your task.

In Windows 7 this is changed somewhat, but you can find it in

Control Panel -> System and Security -> Administrative Tools -> Task Scheduler
You can use "Scheduled Tasks" on windows.
You could also write your application as a "Windows Service". By this, it would run all the time on a machine, without someone creating a scheduled task.