When I click the internet explorer icon, the window maximizes but when I open something in a new window it opens with a minimum window and does not maximize. It will be very helpful if you guys give me a step by step answer. Thank you.

Try expanding the window... and then after it is expanded all the way hold down on the shift key while you close the window.

... then open a new window to see if it opens fully maximized. Let us know how it goes.