Why can’t you just put one huge window on-screen? Well, you can.
To make any window grow as big as it gets, double-click on its title bar, that topmost bar along the top of the window. The window leaps up to fill the screen, covering up all the other windows.
To bring the pumped-up window back to normal size, double-click on its title bar once again. The window shrinks to its former size, and you can see everything that it was covering up.
- When a window fills the entire screen, it loses its borders. That means you can no longer change its size by tugging on its title bar or dragging its borders. Those borders just aren’t there anymore.
- If you’re morally opposed to double-clicking on a window’s title bar to expand it, you can expand it another way: Click on the window’s maximize button, the middle most of the three little boxes in its top-right corner. The window hastily fills the entire screen. At the same time, the maximize button turns into a restore button; click on the restore button when you want the window to return to its previous size.

Or.. you could try this
http://www.friedbeef.com/2007/02/22/how-to-set-a-program-to-always-open-maximized/