In the case of a second monitor, you might have some windows applications that 'know' they go on the right screen. I've never seen a mechanism for Windows to properly recover from windows that want to be too far off the screen for the current resolution. (I'd appreciate any tips if anyone has them.)
Alt-Space, M, then hit an arrow key. For some reason hitting the arrow key attached the mouse pointer to the titlebar of the window, so you can use the mouse to move the window where you want it. Also, while most apps don't require it, hold down Alt while hitting space. Firefox specifically has this issue. Windows apps are supposed to allow users to hit Alt to shift focus to the menu bar, but not all of them work.