This might sound silly, but bare with me, I've had this asked of me before. Are you sure this taskbar is 'extra', or have you perhaps inadvertantly extended the default taskbar?
Put your mouse at the top of the taskbar, and it'll turn the cursor into a little up and down 'arrow' cursor. When you have the arrow cursor, left click and hold, while you move your mouse down (this is the method for resizing your taskbar).
This is just a guess, but I think (since you say you have no spyware that installed an additional taskbar), that you probably resized your own taskbar without realizing it. You wouldn't be the first to do so, trust me (or be the first to ask how it went to the side/top of the computer). Good luck.