The file key.pcf is your subscription key for Propel Accelerator. Normally, this file is automatically placed into Propel Accelerator. In rare cases, Microsoft Windows may ask you to select a program to open the file. Windows typically provides a list of applications. Look for an application called trayctl. If trayctl is not in the list or if Windows does not provide a list, follow these steps. Confirm that Propel Accelerator is installed by clicking Programs from the Start menu. If you don’t see Propel Accelerator in the list, you must download it and install it first.
Locate the file key.pcf and right-click on it.
Select Open With and then select Choose Programs.
Click Other.
Navigate to c:/Program Files/Propel Accelerator/.
Select the file trayctl.exe.