Hi PPRuNE pop,
You've probably at some point dragged the bottom right hand corner of IE to make a smaller window for something.
It should be easy to fix.
Click on a link.
Drag IE window out to the dimensions you want from the bottom right hand corner. When its the correct size, close it using the X in the top right hand corner. Now try a link again. The New window should spring up to full screen.
Hope this helps.
FWyg