There are two requirements here:
- Start the instance each day at a particular time (This is an assumption I made based on your desire to shutdown the instance each day, so something needs to turn it on)
- Run the script and then shutdown
Option 1: Start & Stop
Amazon CloudWatch Events can perform a task on a given schedule, such as once-per-day. While it has many in-built capabilities, it cannot natively start an instance. Therefore, configure it to trigger an AWS Lambda function. The Lambda function can start the instance with a single API call.
When the instance starts up, use the normal Windows OS capabilities to run your desired program, eg: Automatically run program on Windows Server startup
When the program has finished running, it should issue a command to the Windows OS to shutdown Windows. The benefit of doing it this way (instead of trying to schedule a shutdown) is that the program will run to completion before any shutdown is activated. Just be sure to configure the EC2 instance to Stop on Shutdown (which is the default behaviour).
Option 2: Launch & Terminate
Instead of starting and stopping an instance, you could instead launch a new instance using an Amazon CloudWatch Events schedule.
Pass the desired PowerShell script to run in the instance's User Data. This script can install and run software.
When the script has finished, it should call the Windows OS command to shutdown Windows. However, this time configure Terminate on Shutdown so that the instance is terminated (deleted). This is fine because the above schedule will launch a new instance next time.
The benefit of this method is that the software configuration, and what should be run each time, can be fully configured via the User Data script, rather than having to start the instance, login, change the scripts, then shutdown. There is no need to keep an instance around just to be Stopped for most of the day.
Option 3: Rethink your plan and Go Serverless!
Instead of using an Amazon EC2 instance to run a script, investigate the ability to run an AWS Lambda function instead. The Lambda function might be able to do all the processing you desire, without having to launch/start/stop/terminate instances. It is also cheaper!
Some limitations might preclude this option (eg maximum 5 minutes run-time, limit of 500MB disk space) but it should be the first option you explore rather than starting/stopping an Amazon EC2 instance.