The ColdFusion MX 7 Application Server service is started from the Windows Services control panel. If the application service fails, none of the ColdFusion pages will run.
If your ColdFusion Application service is crashing regularly, look at the JVM settings, especially those for minimum and maximum memory. The service will need to be allocated enough memory to handle your application, but not so much that performance is degraded by the Java garbage collector. For larger ColdFusion applications, the JVM should be fine-tuned by someone with experience with that task, as it can really enhance the performance of your application under load.