Check out the doc for the pac demo;
We have a bunch of people pull that demo down, and run pac sim and pac display on the same PC all the time.
The doc should get you up and running.
Correct me if I am wrong, but you don't just want to detect a crashed PC, but a crashed application. In this case, your application is PAC Sim?
Since PAC Sim is running your strategy, and its the one talking to your EB and controlling your process, that's the app that really matters?
Firstly, set up the watch dog function on the EB (Its in the I/O unit configuration dialog box, right near the bottom). This way, if you lose communications, you can set your digital and analog outputs to take on a given state when communications fail between the PC and the EB (for example, if the PC hangs, pac sim hangs, or if an Ethernet cable breaks, or if a switch or router fails) for the given amount of time.
If nothing else, you could configure one of your spare digital outputs with the watchdog and put a noisy alarm with a flashing light. If that comes on, you know something is wrong.
Configure an event reaction on the EB that gets constantly reset by a chart in pac sim.
If something goes bad, the event reaction will fire and sound the alarm.
You never mention using an Ethernet Brain (EB), so I am just guessing, but even if you are using a controller, you can still set up the watchdog, you just wont need the event reaction because you have a controller. In this case, the pac sim strategy resets a counter on the controller. On the strategy on the controller, it tests if the counter gets up to say, three, then sound an alarm.
Hope this helps.