When an object is written as a Win32 service and installed for use by COM through setting the LocalService named value under the AppID key, the ServiceParameters named-value can be set to pass the given parameter on the command line when the service is launched.
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\APPID\
{AppID_value}\ServiceParameters = parameter
The parameter value for the ServiceParameters named-value is any REG_SZ string value. This string is passed on the command line to the service as it is being launched.
For example, the following keys register the c:\mydb\mydb.exe executable to launch as the MyDatabase service when activated remotely. When launched as a service, the process receives "-Service" on its command-line.
HKEY_CLASSES_ROOT\APPID\{c5b7ac20-523f-11cf-8117-00aa00389b71}\LocalService = MyDatabase
HKEY_CLASSES_ROOT\APPID\{c5b7ac20-523f-11cf-8117-00aa00389b71}\ServiceParameters = -Service
Refer to the Win32 SDK documentation about services and the SECSVR sample Distributed COM application for more information about writing, installing, and debugging Win32 services.
LocalService, Registering COM Servers