Reducing the size of toolbars

Hello - I just bought a Dell 15R with Windows 7 a few days ago and I have a question for the experts on this forum - The toolbar that runs horizontally at the bottom of my screen (It came that way) is about one half inch wide, and in my toolbar the icons are: Start, Windows Explorer, Windows Media Player, Firefox Browser icon, and the magnifier icon; on the other side are the usual time and date etc. - How do I reduce the size of the toolbar so I have a bigger page on my screen?  Thanks in advance for your help, I am sure I'll be calling on you again!