You didn't mention which browser you have.
For firefox>right click on ff icon>shortcut tab>next to run select normal,min,or max.
Open internet explorer>resize to your desired size>file>close.
internet explorer should now remember your last saved window size.
When I open a window it is too small and it shows a lot of desktop. I will stetch it to the right size and go file and close but when I open it again it is small again. What gives?