The answer depends on how many hard drives and optical drives you have installed on your computer. When you insert the SD card into you computer do you get a pop-up window asking what you would like to do - with one of the options being "Open Folder to view files"? If yes, then open the folder to view files and you will see the drive letter. If no, open Windows Explorer and then insert the SD card. You should see a new drive letter appear (for example: (E:)). The new drive letter is the appropriate drive of the formatted Memory Card.