Both SLI and Crossfire Can work in windowed mode, the limitation with Crossfire at the moment is the game needs to use DX10/11 for it to work, while SLI will work with DX9 games in Windowed mode. However, in both cases, it doesn't work as well as it would in Fullscreen. Which is a given since games run better in fullscreen in the first place.
That explains it, thanks. My technical skills have been out of practice lately. Early adopter of i7 so I haven't needed to tinker with anything for a while, haha.
Except for my water cooling project last year, that was a lot of fun.