This may work. First, close all open IE windows, then launch IE again. Right-click on any link and choose Open in New Window. Resize the resulting secondary window to the size you want for all secondary windows. Now close the window by holding the Shift key and clicking the X icon in its top-right-hand corner. Set the remaining window to the size you want IE to have when initially launched, and close it in the same way. IE should now remember your preferred window sizes. If it forgets after a while, apply this fix again
How can I get MSIE ver6.0 in winxp to open up in a full size window? As it is now when I open it up or click on a link on the desktop it only opens in a very small window.