Honestly, this workaround is probably a bug in its own right.
Have you ever had a window appear off-screen? Like so far off-screen you can't click the title bar to move it around? Of course you have, you're using Windows. If you can get the standard Restore/Move/Size/etc/close right click menu for the window, and have a keyboard (on screen or otherwise), there's hope.
First of all, getting that context menu: If the window is active, alt-space should make it pop up. In any version of Windows before Vista, right clicking the entry in the taskbar will show it to you; in Vista and later, you may need to either shift-right click or hover your mouse over the taskbar until a preview pane pops up, which you can then right click on. If you're super-lucky you may also be able to click the icon in the top left corner of the window to get it, if that's just barely on-screen enough to click.
Assuming you got the context menu, and that Move is not grayed out, click on Move. Your cursor will turn into a four-directional arrow. Here's the thing that makes most people immediately forget that this menu entry exists: It only works if you click the window header--you know, the thing you click and drag ANYWAY in order to move the window. Since we already established that you can't reach it, you're out of luck, right? Not quite.
Now that your cursor is in the move mode, hit any of the directional arrow keys. In this mode, the window will respond to arrow keys and move, a pixel at a time, in that direction. Huzzah! You can get it back on screen, in a tediously slow fashion! What's that you say? There's more?
Here's the part that's almost certainly a bug: AFTER you have put the cursor into move mode and AFTER you have hit an arrow key, the window treats you like you're holding down the mouse button--the window follows your mouse until you click the button again. That means click Move, hit an arrow key, then move your mouse towards the center of the screen, and the window is instantly fully in view.
Sounds silly? It's saved me more than a few times. I can think of no logical reason why the Move entry is still in the standard window context menu, but that trick has worked as far back as I can remember, maybe into the earliest days of Windows.
If you're wondering, yes, it came to mind because I had to use it, even now after years of using Windows. Since I sometimes use this computer with multiple monitors, and sometimes don't, windows popping up off-screen just happens. Blast it all, but sometimes that's just how it goes.