Since reinstalling Windows didn't fix it, it may be some problem with your video, though it doesn't seem likely.
I keep going back to where you said that you have to pull the window down like a curtain.
Doesn't the window snap to full screen when you click the Maximize button?
If that doesn't happen it's very strange!
I guess I would try updating video drivers and if you can get a high resolution video monitor to try, you could do that.
I know that my ATI video card has a number to setting relating to how windows appear on the screen though I never mess with them.
Make sure the resolution is set to the native resolution for your monitor.
I found this on another forum....
"For those looking for a solution to this...