Visual Studio 2010, 2015 - windows off screen

You can move any window in Windows using keyboard shortcuts. First, give the focus to the window, even if you can't see it, by toggling the tool window. Then press alt+space, 'm', press an arrow key, and then move the cursor in the visible screen region. If all goes well, the window should have followed. You can practice the trick with a notepad window. Note that the mnemonic depends on your Windows language, it's 'l' in French.

Have you tried the Window menu | Reset Window Layout command? Obviously that will do more than you really want, but it is perhaps better than nothing