@atlantis
I’m certain that you have only a single hard drive on your computer. Here’s how you can find out, as easily as possible.
Go to My Computer (or whatever the icon is called on your Windows desktop that represents “My Computer” – it might be called ‘whatever the computer name is’, instead)
Right-click the icon and select “Properties”
Click the tab for “Hardware”
Click on “Device Manager”
When the list is generated, click the ”+” next to “Disk Drives”. That will give you a list of the physical drives in the system. (I expect that you have only one shown, but hold on, we’re not done yet.)
Now right-click on the disk drive name and click “Properties” again.
Click the tab for “Volumes” and the button at the bottom of the dialog box for “Populate”. This will list all of the names of the various partitions on your hard drive, and their sizes.
And now you know what you have.