Do you mean an Internet explorer window? there is no tick box to tick.
If you right-click the Internet Explorer icon on the Quick Launch toolbar (or your IE
shortcut in Start Menu) and select Properties.
On the Shortcut tab, next to Run, click the down arrow and select Maximized.
This doesn't work for windows opened by clicking hyperlinks.
Start IE, right click any link on a web page, and select Open in a New Window.
Go back to the first IE window you opened and close it.
Return to the second window and manually drag it to fill the screen.
(Do not use the maximize button, for that's a temporary setting that will not be
Now press the Ctrl button, and close this second window, holding the Ctrl button
depressed, using 'close' in the File menu (important!).
This should force Windows to remember the settings, and windows will now open