Hi nagswoman,
I don't know if this will work in Vista, but it worked in XP when I had windows tiled and just closed them instead of undo tile. Windows kept remembering the size and position of the tiled windows similar to what you describe.
I opened a couple windows and tiled them, then clicked undo tile. I resized each before closing them, and Windows remembered the size and position after that.
Hope that helps.
T.
