When installing MongoDB as a Windows service with a single hyphen before the "install" parameter, the Windows service will be created. However, when attempting to start the service, the service will fail to start. Alternatively, if you install using two hyphens before the "install" parameter, the service will start just fine.

For example, this will create a Windows service that cannot be started:
> "C:\Program Files\MongoDB\bin\mongod.exe" -install --logpath "C:\MongoLog.txt"

This will create a Windows service that CAN be started (notice the two hyphens before "install"):
> "C:\Program Files\MongoDB\bin\mongod.exe" --install --logpath "C:\MongoLog.txt"