I know some manufactures have different ways they produce their setups, but most of the time its a partition and not another hard drive. What it does is store the System Backup / Restore on one partition so that you can reset the laptop to factory settings and the main "hard drive" (usually C prompt) is the partition you use on a daily basis. Unless you physically looked inside the laptop and saw 2 different hard drives, it should be just one hard drive that is split partitions. What is the make and model of this laptop? We can determine what setup you have with that information.