photoshop help?

My Photoshop is acting weird. When I do a window around something, it adds another x number of pixels to the rectangle. Why is this? At first, it made the area beyond what I chose fade out, to the edge of the image. Then the fade stopped ,but it still adds the pixels. Can anyone tell me how to reset it? I'm hoping I don't have to reinstall it.

In other news, my boss says his arrow keys are reversed, so when he hits the left arrow, his cursor goes to the right.