There is only one size for the SecurityCenter window.
You must have your display settings at an abnormal level for this to happen as SecurityCenter normally would only fill less than one quarter of the screen See attached image - click to enlarge).
Check your browser settings under Tools/Internet Options/General - Appearance and make sure under the Accessibility tab that nothing is selected.
Then download and run the Virtual technician.
thanks ex-brit but that wasn't the problem. I had already run virtural technician. The box used to come up about 2 inches longer horizontally; vertically, it is the same size. I guess I'll just live with it. I've tried everything I could think of and none of it worked so as long as I can still scan and use MVT to fix, that's what I'll do. Thanks again
Was it a popup window that you are talking about? I suppose you tried to click & drag it into view? It's not always possible, just a thought.
You could try Technical Support Chat available via THIS link, if you wish.