Here. Raymond explains why the taskbar defaults to the bottom of the screen (because old apps would position themselves under it a lot when it was on top). Since I defected from the Mac, I always move mine to the top and like it, but did have problems for *years* about apps moving up under there.
For those few that still do, I've long since memorized the key sequence: Alt, Space, M, which flips a window into "Move Mode" and lets me use the arrows to move it down. I can understand why MS didn't want to teach everyone that and instead just put the taskbar at the bottom. : )