I had the same problem. After much frustration, I found the source of the problem for me, and it might be the same for you. I have an nVidia gpu, and under the control panel, there is a task under "Display" called "Adjust Desktop Size and Position". In that menu, there are a few scaling options. Select "Aspect Ratio" so that the ratio is maintained, and any time you have a fullscreen application (ie. in-game BINK videos), it will scale it to fill the screen with black bars if the aspect ratio of the media is different than your screen.
That fixed the not-so-stretching problem.
On a side note, there are some BINK videos that are 4:3 with their own black bars (the opening title and end credits). These can be cropped with RAD video tools if you want to go through the effort.
VC
