How to cascade windows vertically or horizontally in Windows 7?

"I guess you mean ""Tile vertically or horizontally""?

You can use Aero Snap: move 1 window on the left side of the screen and the other windows on the right side of the screen. Both will maximize to half the size of the screen, making it easy to view both at the same time."

To cascade or tile only a specific group (say several Excel windows open at the same time), hit the shift key first then right click and select the cascade or tile option you want. Note, this assumes the individual windows are being combined; that is an optional property for the task bar.