Default maximized size and position changeable.

I've decided to use my task bar on the top edge of my screen, hidden, but
when I want to close or minimize maximized windows, I keep bumping into the
taskbar, and making it open in the way of the controls. I found a program
that can control where and what size all the maximized are, and found putting
20 pixels of dead space at the top of my screen works very well, and even
looks decent, but I'd rather make the changes at the XP registry level, so
when I don't want to use the tricky program, I'll still have that benefit.
Does anyone know how I can make those changes to XP?

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Michael Ateek