Changing Win7 taskbar position messes up screen?

[Gurachn]

I have been running WinSPWW2 on my dual monitor setup (Laptop+ external) windowed and desktop resolution (1680x1050 on the external monitor) for some time now, with no problems.

I recently decided to move the taskbar from the bottom to the top of the screen(no auto-hide), and this eventing fired up the game to find that the game display was skewed diagonally across the screen.
I tried moving the taskbar back down to the bottom, but now it doesn't want to play nice at all. I can set it windowed to any other res, but the desktop setting continues to be messed up.

Any ideas how to fix this?