You should ask further questions on the same topic on the same thread, not start a new one.
What specifically is listed when you open the "mount" icon? Are you looking for the files on your hard disk, or just for the hard disk itself?
In Windows, your files are accessible when you boot. In linux, you have to mount the device (which includes a hard drive partition) that the files are on before they are accessible. All of your Puppy files will be accessible on boot, but if you are looking for files on another hard drive partition, you'll have to mount the partition.
If you are looking for your puppy files, you need to open Rox-filer - that's the icon that looks like a house. For files on another partition or an external drive, Rox-filer will open showing the files on the drive when you mount the drive.
Give some more information about exactly where the files you want to access are, and what devices are listed when you click "mount", and you can get some more specific guidance.