Since installing Windows 7 every time you play a game it wont go to widescreen leaving a black strip on both sides of the screen adjusting the resolution in the games options does nothing how to fix

I would suggest trying two things:

1) Update your video drivers. Many driver packages (nVidia and ATI included) may allow you to change the way in which a "full screen" application will fill the screen. Look specifically for an option to change the way in which non-native resolutions scale.

2) Check your monitor settings. Again, look for options to change the way images will scale.