What have I done wrong?

I recently re-installed the free 30 day version of Proscan.I had it couple fo momths back but never got round to registering it the first time.Trouble is,this time the display doesn't quite fit into my computer monitor screen.It did the first time,but now it just seems too big and no amount of screen res adjustment will cure it.Anybody help.
I've put a couple of 'before and after' pics in 'photos' so you can see what I mean.