Well after a lot of tries and fails (pretty much like playing the game
) I discovered that the issue is related to the refresh rate, for some reason in WIN7, with my monitor and certain games (Super Meat Boy, COH, Driver San Francisco, etc) when I choose the maximun resolution (native) the refresh rate is set by the monitor to 59hz and that makes the image to look stretched and pushed to the right.
The fix is to download RIVATUNER, and choose the option to "Low level refresh setting" and then create a rule: your resolution [1440x900 in my case] and 60hz as refresh rate (it may be other, but I haven't tested)
You have to keep open the program and run the game and it will show correctly... however for some reason is more laggy than playing it in window mode.
I hope this will be useful to someone else